Happy Days is probably the most famous of these examples (https://tvtropes.org/pmwiki/pmwiki.php/AscendedExtra/LiveActionTV) as Fonzie (Henry Winkler) became the undisputed star (https://tvtropes.org/pmwiki/pmwiki.php/BreakoutCharacter/LiveActionTV) after Ron Howard left. Then again, Fonzie was for all intents and purposes, already ostensibly the co-lead during Happy Days' heyday.

I'm right now going off the top of my head, but there's A Different World. Whitley and Dwayne became the de facto lead characters after Denise left following Season 1.

On Beverly Hills, 90210, Kelly officially became the female lead upon Brenda's departure. And when Jason Priestley (Brandon) left, Jennie Garth became the first billed star.

On ER, Noah Wiley (John Carter), went from being the fourth billed actor in the pilot, to the main character in Season 9 (he was the only original cast member left at that point).

Jimmie Walker (and to a lesser extent and officially billing-wise, Jan'et DuBois) all but became this after John Amos and Esther Rolle (temporarily) left Good Times.

A most recent example that I can think of is Bunk'd on Disney Channel. Lou officially became the lead character upon Emma, Ravi, and Zuri's departures at the end of Season 3.

Mila Kunis became the first billed star in That '70s Show's last season (https://en.wikipedia.org/wiki/That_%2770s_Show_(season_8)) after Topher Grace left.

I don't know if this counts, but Zack Morris became the lead character when Good Morning, Miss Bliss (which as the title would suggest, centered on Miss Bliss played by Hayley Mills) on Disney Channel was converted into Saved by the Bell on NBC.

I don't agree with some of these. For example, no one was really the "star" of ER. It was a solid ensemble show with all the major characters/actors each getting their turn in the spotlight.

Jimmy Walker and Henry Walker were breakout stars, but I don't think they ever became the "leads" in the sense that you're talking about. No one thinks of Good Times becoming "The Jimmy Walker/JJ Show" once John Amos left or Happy Days becoming "The Henry Winkler/Fonz Show" once Ron Howard left.

Grady on Sanford and Son for a short time.

I don't agree with some of these. For example, no one was really the "star" of ER. It was a solid ensemble show with all the major characters/actors each getting their turn in the spotlight.

Jimmy Walker and Henry Walker were breakout stars, but I don't think they ever became the "leads" in the sense that you're talking about. No one thinks of Good Times becoming "The Jimmy Walker/JJ Show" once John Amos left or Happy Days becoming "The Henry Winkler/Fonz Show" once Ron Howard left.

Well think about it this way, during Season 1 of Happy Days, Henry Winkler as far as I can tell, wasn't even billed during the opening (https://www.youtube.com/watch?v=okjJHV5E3bk). In Season 2, Winkler was fourth billed (https://www.youtube.com/watch?v=HI_xnsz_l3s) behind Ron Howard, Marion Ross, and Anson Williams. It wasn't until Happy Days switched to being a multi-camera show that Winkler became second billed behind Ron Howard. As a matter of fact, during the height of Happy Days' popularity, the network wanted to call it Fonzie's Happy Days (https://books.google.com/books?id=_3XnpqmYAxcC&pg=PA38&lpg=PA38&dq=rename+fonzie%27s+happy+days+network&source=bl&ots=q8xC-zeCKa&sig=ACfU3U0fs56kagX9HL2G_mSqkPy7vN0LNg&hl=en&sa=X&ved=2ahUKEwiv-p_ilarkAhVPC6wKHfgtBQAQ6AEwEnoECAoQAQ#v=onepage&q=rename%20fonzie's%20happy%20days%20network&f=false), but didn't because Henry Winkler and Ron Howard objected to it. It's kind of naive to not immediately assume that Happy Days for all intents and purposes officially became "The Fonzie Show" once Ron Howard left.

TMC Let's recap:

Here's the title of thread:

Supporting characters who suddenly became the lead after the "star" leaves

With respect to Happy Days, Ron Howard didn't suddenly leave, he left after the 7th season, and by the time he left he was no longer playing the main character as you point out in two different responses. That said, why do you mention the series, it doesn't fit your own criteria?

TMC Let's recap:

Here's the title of thread:

Supporting characters who suddenly became the lead after the "star" leaves

With respect to Happy Days, Ron Howard didn't suddenly leave, he left after the 7th season, and by the time he left he was no longer playing the main character as you point out in two different responses. That said, why do you mention the series, it doesn't fit your own criteria?

To clarify, I didn't say that Ron Howard himself, "suddenly left". I said "supporting characters who suddenly became the lead (meaning, the first billed star) after the designated star leaves".

I agree with TMC: Fonzie went from second banana (or even fourth/eighth/tenth banana) to the star of the show.

To clarify, I didn't say that Ron Howard himself, "suddenly left". I said "supporting characters who suddenly became the lead (meaning, the first billed star) after the designated star leaves".


As you know Fonzie was no longer a supporting character when Howard left, he became the lead character in season 3, Howard left after season 7.

Supporting characters who suddenly became the lead after the "star" leaves:

I'll give this a shot, 8 Simple Rules might fit this category. Katey Sagal was actually a costar, but the show was focused on John Ritter's character, with his untimely passing she took over as the lead character.

This is an obscure one, My Living Doll. Robert Cummings was the male lead in this series but asked out of his contract, and was released after the 21st episode. The male lead for the remainder of the series (5 episodes) was assumed by Jack Mullaney's character, Peter Robinson.

Supporting characters who suddenly became the lead after the "star" leaves:

I'll give this a shot, 8 Simple Rules might fit this category. Katey Sagal was actually a costar, but the show was focused on John Ritter's character, with his untimely passing she took over as the lead character.

This is an obscure one, My Living Doll. Robert Cummings was the male lead in this series but asked out of his contract, and was released after the 21st episode. The male lead for the remainder of the series (5 episodes) was assumed by Jack Mullaney's character, Peter Robinson.

Depending on who you ask, Bob Cummings' departure was either because he felt that the show (http://mercurie.blogspot.com/2014/09/50-years-ago-today-my-living-doll.html) was so bad (https://www.tvobscurities.com/articles/my_living_doll/) that he asked to be written out (https://search.proquest.com/docview/116738337) before the first season was finished. Another theory is that he was unhappy over the size of his role. And then there's fact that Cummings at one point or another in his life, had a crippling (https://bjorkbloggen.com/2016/01/13/robert-cummings-from-being-a-praised-actor-to-being-hooked-on-methamphetamine/) meth addiction (https://en.wikipedia.org/wiki/Robert_Cummings#Drug_addiction).

Depending on who you ask, Bob Cummings' departure was either because he felt that the show (http://mercurie.blogspot.com/2014/09/50-years-ago-today-my-living-doll.html) was so bad (https://www.tvobscurities.com/articles/my_living_doll/) that he asked to be written out (https://search.proquest.com/docview/116738337) before the first season was finished. Another theory is that he was unhappy over the size of his role. And then there's fact that Cummings at one point or another in his life, had a crippling (https://bjorkbloggen.com/2016/01/13/robert-cummings-from-being-a-praised-actor-to-being-hooked-on-methamphetamine/) meth addiction (https://en.wikipedia.org/wiki/Robert_Cummings#Drug_addiction).

Pairing a fifty something actor and a twenty something actress wasn’t a good idea.

Pairing a fifty something actor and a twenty something actress wasn’t a good idea.

Yeah, Bob was 54 years old, Newmar 31, although these illogical age differences were not uncommon in movies of that era (take a look at some of the pairings with Crosby, Grant, Astaire, Hope & Stewart) TV is a more intimate medium. On top of that, by all reports Bob had a huge ego and probably thought if the series failed he'd be blamed, and at his age he might not get another shot.

We’re conflating character prominence with billing. They’re often related, but not always. “ER” is a great example - Noah Wyle didn’t suddenly become the lead when Anthony Edwards left. He got top billing, but he was always a prominent member of the ensemble. Similarly, when Wyle left, Goran Visnjic was billed first, but he didn’t become the lead.

Same for Mila Kunis on “That 70s Show”. The original six actors were billed alphabetically, and this continued for the original four after the departure of Topher Grace and Ashton Kutcher. Mila Kunis didn’t become the lead even though she got top billing in the final season.

The Office (NBC) when Steve Carell left, season 8 and 9. Terrible seasons. Show started going downhill though by Season 6 or so.

I wouldn't say there was a single lead after Michael (Steve Carell) left, but it was kind of between Jim, Dwight and Andy.

Dallas: Barbara Bel Geddes left in season 8 (1984-85) due to illness; Patrick Duffy received top billing. However, that was kinda by default, given the cast appeared in alphabetical order.

Bel Geddes returned the following season, whereas Duffy left. :p

Supporting characters who suddenly became the lead after the "star" leaves:

I'll give this a shot, 8 Simple Rules might fit this category. Katey Sagal was actually a costar, but the show was focused on John Ritter's character, with his untimely passing she took over as the lead character.



8 Simple Rules didn't last that long after John Ritter passed away, so it's hard to say Katey Sagal took much lead, although she was the sole parent. It also was a tragic circumstance and the show was too tied to John Ritter. They did add James Garner and David Spade, but the series was moved and cancelled in a season.

Sara Gilbert (Darlene) replacing Roseanne Barr (Roseanne).

Although technically it's a new show or spinoff, The Conners. Just that it's hard to say it's a spinoff or new show because 90% of the show is the old show: the house, the entire rest of the family (cast), premise of the show, opening theme and pretty much everything else that went with the old show. Last episode I saw of The Conners, an old clip of Darlene and David as teenagers was shown (from Roseanne).

8 Simple Rules didn't last that long after John Ritter passed away, so it's hard to say Katey Sagal took much lead, although she was the sole parent. It also was a tragic circumstance and the show was too tied to John Ritter. They did add James Garner and David Spade, but the series was moved and cancelled in a season.Katey Sagal was definitely the lead after John Ritter died. And there are more episodes without him (45) than with him (31), so it still lasted awhile before being cancelled.

Sara Gilbert (Darlene) replacing Roseanne Barr (Roseanne).

Although technically it's a new show or spinoff, The Conners. Just that it's hard to say it's a spinoff or new show because 90% of the show is the old show: the house, the entire rest of the family (cast), premise of the show, opening theme and pretty much everything else that went with the old show. Last episode I saw of The Conners, an old clip of Darlene and David as teenagers was shown (from Roseanne).

I always assumed that John Goodman and Laurie Metcalf were the defacto leads with Roseanne now out of the picture. Maybe because they were the "adults" of the household now.

I always assumed that John Goodman and Laurie Metcalf were the defacto leads with Roseanne now out of the picture. Maybe because they were the "adults" of the household now.

It's much more Darlene as the central person.

Katey Sagal was definitely the lead after John Ritter died. And there are more episodes without him (45) than with him (31), so it still lasted awhile before being cancelled.

Lasted awhile I disagree. I think 3 seasons of a series altogether, with just 1 full season, that being the season it got canceled, without Ritter is very limited. It was a tragic circumstance and the sadness of the real life death of John Ritter probably left little from ABC to continue the show with Katey Sagal truly as the lead in single parent type sitcom. It got the Friday night death slot and rumors circulated of cancellation after Ritter's death. The show introduced two big names (James Garner, David Spade) for in-fill of a male adult role in the house, putting less lead on Katey Sagal.

Fonzie (Happy Days), Whitley (A Different World), Kelly (Bev. Hills 90210) are stronger examples.

I'd add Urkel on Family Matters even though there was no star that left while he became big on the show. There was daughter Judy, Jo Marie Payton in the very last season although she wanted to leave the show earlier but couldn't because of contract, and Telma Hopkins in the middle for awhile. But Urkel became indispensable to Family Matters writing, while the rest of the family had storylines around his character.

Lasted awhile I disagree. I think 3 seasons of a series altogether, with just 1 full season, that being the season it got canceled, without Ritter is very limited. It was a tragic circumstance and the sadness of the real life death of John Ritter probably left little from ABC to continue the show with Katey Sagal truly as the lead in single parent type sitcom. It got the Friday night death slot and rumors circulated of cancellation after Ritter's death. The show introduced two big names (James Garner, David Spade) for in-fill of a male adult role in the house, putting less lead on Katey Sagal.

Fonzie (Happy Days), Whitley (A Different World), Kelly (Bev. Hills 90210) are stronger examples.[/QUOTE]

What are you talking about! Let's start at the beginning here's the title of the thread:

Supporting characters who suddenly became the lead after the "star" leaves

Where is there any reference in this title to the length of time the series remained on the air after the star left? You're making things up.

An additional point, Fonzie absolutely, positively is not a strong example. Fonzie did not become the lead character after Ron Howard (Richie being the original lead character) left the series. Howard left the series after the seventh season, Fonzie had been the lead character for years, there's no question about that. Actually another thread could be started naming series where the original lead character gives way to a new lead character (the hook being that the original lead character remained on the series).

I don't agree with some of these. For example, no one was really the "star" of ER. It was a solid ensemble show with all the major characters/actors each getting their turn in the spotlight.

Jimmy Walker and Henry Walker were breakout stars, but I don't think they ever became the "leads" in the sense that you're talking about. No one thinks of Good Times becoming "The Jimmy Walker/JJ Show" once John Amos left or Happy Days becoming "The Henry Winkler/Fonz Show" once Ron Howard left.

Well to put things into some perspective (https://www.theatlantic.com/entertainment/archive/2014/09/fifteen-years-at-county-general-definitively-ranking-all-of-ers-doctors-and-nurses/380164/):
17. Abby Lockhart (Maura Tierney (https://www.afterellen.com/general-news/38991-maura-tierney-says-goodbye-to-er))

(Seasons 6-14, Guest Star in Season 15) Starting out as a nurse and rising to senior ER (https://www.reddit.com/r/ershow/comments/bedq6k/who_was_the_most_important_character_on_er/) doctor, Abby was the third longest-running character on the show and the de facto lead once Carter (https://www.reddit.com/r/ershow/comments/aic7gd/who_was_supposed_to_be_the_new_carter/) left. For her troubles she was saddled with the heaviest baggage of anyone on ER, from her bipolar mother (Sally Field) to struggles with alcoholism to being assaulted by her neighbor and kidnapped by gang members. Abby's drama often overwhelmed her core character, always played with as much dignity and strength as Tierney could muster.

Another ER example is Julianna Margulies overtaking Sherri Springfield as the female lead after about the first two seasons after Springfeld suddenly quit. The story goes that after Julianna won an Emmy (in the supporting category) she was threatening to quit ER. The reason was because she really didn't have a storyline outside of being reduced to walking the halls and shouting out medical terms. But then Springfeld as I said abruptly left, which wound up allowing Julianna to receive more screen time.

It was a tragic circumstance and the sadness of the real life death of John Ritter probably left little from ABC to continue the show with Katey Sagal truly as the lead in single parent type sitcom. It got the Friday night death slot

Ratings were definitely not the reason 8 Simple Rules was canceled. It was doing better than other shows on Friday night that got renewed that year. I think you are right John Ritter's death probably made ABC's decision to cancel which isn't fair. The cast and writers still did very well keeping it an entertaining show. I would have rather seen 8 Simple Rules go on than Hope & Faith or Less Than Perfect.

On Petticoat Junction, when Bea Benaderet passed away from lung cancer in 1968, Edgar Buchanan became the star and June Lockhart was added as Dr. Janet Craig following the cancellation of Lost in Space. The changes didn't help and Petticoat Junction was gone in 1970, replaced by the sitcom that would be one of the first classics of the 70s, The Mary Tyler Moore Show.

They were both the main stars, but after Shirley left, Laverne became the main star.

What are you talking about! Let's start at the beginning here's the title of the thread:

Supporting characters who suddenly became the lead after the "star" leaves

Where is there any reference in this title to the length of time the series remained on the air after the star left? You're making things up.

An additional point, Fonzie absolutely, positively is not a strong example. Fonzie did not become the lead character after Ron Howard (Richie being the original lead character) left the series. Howard left the series after the seventh season, Fonzie had been the lead character for years, there's no question about that. Actually another thread could be started naming series where the original lead character gives way to a new lead character (the hook being that the original lead character remained on the series).

Go re-read my comment:
8 Simple Rules didn't last that long after John Ritter passed away, so it's hard to say Katey Sagal took much lead, although she was the sole parent. It also was a tragic circumstance and the show was too tied to John Ritter. They did add James Garner and David Spade, but the series was moved and cancelled in a season.

You chose to skip over my comment, so let me repeat it again: ABC didn't provide much lead for Katey Sagal, if it introduced James Garner and David Spade in the cast. And the show got cancelled pretty quickly.

ABC didn't want to do a single mom raising her kids show. Add some other relative adults living in the house, and those who are famous actors too?

Happy Days lasted many years with Fonz as lead after Rich left. Of course, duration and actual lead matters.

Emma Kenney as Debs became the lead female character on shameless this season after Emmy Rossum as Fiona left the show.

Andy Sipowicz officially became the main character on NYPD Blue after Bobby Simone died, although Andy was always the main character from day one in my opinion. Both David Caruso and Jimmy Smits always got top billing before that.

Clint Eastwood in the last year of Rawhide after Eric Fleming left.

Clint Eastwood in the last year of Rawhide after Eric Fleming left.Clint Eastwood must have just been getting started out then to have second billing to Eric Fleming. I had never heard of him.

The main reason you never heard of Eric Fleming was because he passed away a year after Rawhide went off.

Go re-read my comment:
8 Simple Rules didn't last that long after John Ritter passed away, so it's hard to say Katey Sagal took much lead, although she was the sole parent. It also was a tragic circumstance and the show was too tied to John Ritter. They did add James Garner and David Spade, but the series was moved and cancelled in a season.

You chose to skip over my comment, so let me repeat it again: ABC didn't provide much lead for Katey Sagal, if it introduced James Garner and David Spade in the cast. And the show got cancelled pretty quickly.

ABC didn't want to do a single mom raising her kids show. Add some other relative adults living in the house, and those who are famous actors too?

Happy Days lasted many years with Fonz as lead after Rich left. Of course, duration and actual lead matters.

I'll take another shot at this, in reverse order:

Fonzie (Winkler) was the lead character years before Richie (Howard) left the series, there can't be any serious question of that fact. Winkler discussed the change and the subsequent conversation he had with Howard who wanted what was best for the show (Howard wasn't happy but what could he say, the show worked better and was more successful). As far as billing is concerned, those arrangements are worked out before the series began (in his book about Gilligan's Island Schwartz discusses the nuances of these agreements).

With respect to 8 Simple Rules, Segal was the lead after the passing of Ritter.
The fact that they added additional characters that became regulars doesn't change that fact.

I don't necessarily think that Charmed fits the bill, since it was always more of an ensemble show. But (since I had already mentioned Shannen Doherty concerning 90210) on that, Piper became the defacto leader of the "Charmed Ones" after Prue died. Holly Marie Combs even got a special "And ..." credit come Season 4. And Alyssa Milano went from being the last billed sister to being first after Shannen Doherty's departure.

On Sliders, Cleavant Derricks became this by default when by the fifth and last season, he was the only original cast member who was still left. Jerry O'Connell had departed after the prior season.

It's much more Darlene as the central person.

Now that I thought about it, if you consider Season 1 of Fuller House to be Season 9 of Full House, then there's DJ replacing Danny as the central character.

Charlie's Angels - After Kate Jackson left, Jaclyn Smith went from being the last billed Angel to being the first billed and the lead of the show.

I don't agree with some of these. For example, no one was really the "star" of ER. It was a solid ensemble show with all the major characters/actors each getting their turn in the spotlight.

Jimmy Walker and Henry Walker were breakout stars, but I don't think they ever became the "leads" in the sense that you're talking about. No one thinks of Good Times becoming "The Jimmy Walker/JJ Show" once John Amos left or Happy Days becoming "The Henry Winkler/Fonz Show" once Ron Howard left.
HAPPY DAYS became "The Fonzie show" in the 2nd season (which is when it "jumped the shark")

HAPPY DAYS became "The Fonzie show" in the 2nd season (which is when it "jumped the shark")

I couldn't disagree more with that statement if I tried. I'm not saying it never "jumped the shark" but I strongly disagree that Happy Days was a bad show by the 2nd season. I think Happy Days was a better show than a lot of people give it credit for.

Ed.

I couldn't disagree more with that statement if I tried. I'm not saying it never "jumped the shark" but I strongly disagree that Happy Days was a bad show by the 2nd season. I think Happy Days was a better show than a lot of people give it credit for.

Ed.I agree Happy Days was a great show. If anything the 1st season might have been one of the weakest when Fonzie's role wasn't fully developed yet. And viewers must have liked it throughout too for Happy Days to last 11 seasons. Very few sitcoms come close to that longevity.

I don't know if Mom counts, but the show was originally meant to focus on Anna Faris' character. Basically, it was intended to be a show about about a divorced mother in AA dealing with her ex-husband, previously estranged mother, kids, and job. But by the end of it, it was really about Allison Janney's character and her AA friends. Even when Anna Faris was still on the show, her kids and ex-husband were long out of the picture.

Although the show is an ensemble, on Showtime's The Chi, the original lead was Jason Mitchell as Brandon. He was fired after sexual misconduct just after the second season.

The show continued for another two seasons and renewed for a fifth season. It will last longer without Brandon and few other originals. I think that Emmett, who was present since season 1 is the lead, or a lead, but it's hard to count for how many minutes each character gets per season, as it's an ensemble. And there is more woman character representation, a transgender added also, and the show has become more like a Black primetime soap opera when originally, it was compared to The Wire, a very different type of show.

Emma Kenney as Debs became the lead female character on shameless this season after Emmy Rossum as Fiona left the show.

Since there isn't a Shameless board...:
Emma Kenney: Shameless set "became a more positive place" after Emmy Rossum's left the show (https://hollywoodlife.com/2021/10/13/emma-kenney-emmy-rossum-shameless-more-positive/)

Kenney called out her former co-star, whom she hasn't spoken to in more two years, on the Call Her Daddy podcast. “It was weird at first for sure but it also… the set became more of a positive place, I’m not gonna lie," Kenney said of Rossum's exit, according to Hollywood Life. "I remember pre (Rossum) leaving, I’d go to set some days and I’d be very anxious about having a scene with her because if she had a bad day, she made it a bad day for everybody.” It wasn’t always bad blood between the two, however, as Kenney felt like she had a “sister relationship” with Rossum when the two started filming together. "Growing up I definitely took a note from — not just her in particular — but people and things that I want to carry on in my life and things I do not want to carry on in my life," Kenney said during her podcast. Still, Kenney says she has no bad feelings for Rossum. “I have a lot of love for Emmy, I’ve known her for so long," says Kenney. "We haven’t spoken in years. But that’s okay. I have a lot of love for her, and I hope she finds her happiness.”

A Differant World when Lisa Bonet left after season 1 and Jasmine Guy stepped in

I don't know if Mom counts, but the show was originally meant to focus on Anna Faris' character. Basically, it was intended to be a show about about a divorced mother in AA dealing with her ex-husband, previously estranged mother, kids, and job. But by the end of it, it was really about Allison Janney's character and her AA friends. Even when Anna Faris was still on the show, her kids and ex-husband were long out of the picture.

I have been thinking a lot about this lately. Not only did we lose Christy's children, ex-husband, and her daughter's boyfriend, we also lost her co-workers at the restaurant. The show slowly stopped revolving around Christy and eventually became centered around Bonnie and her husband, and Bonnie's friends. In some ways, it almost makes sense that Christy doesn't even appear in the final season: her storyline and her characters eroded over the years. Once there was a set for Bonnie's husband's bar, but no set for Christy's workplace, the writing was on the wall.

How about Heather Locklear on Spin City? She was added in season 4 while Michael J Fox was still there. When Fox left after season 4, she moved up to co-lead along with Charlie Sheen who was added for season 5.

How about Heather Locklear on Spin City? She was added in season 4 while Michael J Fox was still there. When Fox left after season 4, she moved up to co-lead along with Charlie Sheen who was added for season 5.I don't think Heather Locklear was co-lead, haven't seen Spin City in awhile but it seems like Charlie Sheen just replaced Michael J. Fox as the sole lead. Heather might have been billed 2nd but her character's role wasn't increased, just a different lead actor took over as the main character.

I don't think Heather Locklear was co-lead, haven't seen Spin City in awhile but it seems like Charlie Sheen just replaced Michael J. Fox as the sole lead. Heather might have been billed 2nd but her character's role wasn't increased, just a different lead actor took over as the main character.


Well, I remember she and Sheen were both shown together in the intro for season 5, so that's why I though she was co-lead. But I really didn't watch much after Fox left.

https://www.youtube.com/watch?v=Ia9XwAV-ayE

Not that she wasn't always the out and out "lead", but Wendi McLendon-Covey on The Goldbergs had to do a lot more of the heavy lifting for the adults in the main cast after George Segal died and Jeff Garlin was forced to leave the show due to his on-set misconduct.

The Office (NBC) when Steve Carell left, season 8 and 9. Terrible seasons. Show started going downhill though by Season 6 or so.

I wouldn't say there was a single lead after Michael (Steve Carell) left, but it was kind of between Jim, Dwight and Andy.

The Facts of Life is another show where after Charlotte Rae left, it was hard to say if there was officially a single lead. Cloris Leachman was by design, supposed to be the "star" in the last two seasons, since she was now first billed, was the most "known" actor/actress among the main cast, and was now the central "adult" figure.

The Facts of Life always felt more like an ensemble show to begin with but with Mrs. Garrett gone, there went the initial point of the show's existence (i.e. it being a spin-off of Diff'rent Strokes).

Lasted awhile I disagree. I think 3 seasons of a series altogether, with just 1 full season, that being the season it got canceled, without Ritter is very limited. It was a tragic circumstance and the sadness of the real life death of John Ritter probably left little from ABC to continue the show with Katey Sagal truly as the lead in single parent type sitcom. It got the Friday night death slot and rumors circulated of cancellation after Ritter's death. The show introduced two big names (James Garner, David Spade) for in-fill of a male adult role in the house, putting less lead on Katey Sagal.

Fonzie (Happy Days), Whitley (A Different World), Kelly (Bev. Hills 90210) are stronger examples.

What are you talking about! Let's start at the beginning here's the title of the thread:

Supporting characters who suddenly became the lead after the "star" leaves

Where is there any reference in this title to the length of time the series remained on the air after the star left? You're making things up.

An additional point, Fonzie absolutely, positively is not a strong example. Fonzie did not become the lead character after Ron Howard (Richie being the original lead character) left the series. Howard left the series after the seventh season, Fonzie had been the lead character for years, there's no question about that. Actually another thread could be started naming series where the original lead character gives way to a new lead character (the hook being that the original lead character remained on the series).

A Different World is a unique example with Whitney being moved up to being the lead character, despite being more of a supporting type. It was almost like a spinoff happening within an existing show. And they had to retool her somewhat and make her more sympathetic and universal, while still retaining the qualities that made her Whitney.

12 Supporting TV Actors Who Stole The Show From The Lead (https://www.looper.com/1706434/supporting-tv-actors-who-stole-the-show/)

These actors were originally cast as supporting characters on their respective TV shows, but eventually broke out as their series' main attraction.

8 Simple Rules didn't last that long after John Ritter passed away, so it's hard to say Katey Sagal took much lead, although she was the sole parent. It also was a tragic circumstance and the show was too tied to John Ritter. They did add James Garner and David Spade, but the series was moved and cancelled in a season.

To me, a similar sort of thing happened with Petticoat Junction. It too, tried to continue despite the tragic death of its star, Bea Benaderet. And like 8 Simple Rules, Petticoat Junction was simply way too tied to Benaderet's character.

With that being said, you can argue that Linda Kaye Henning (Betty Jo) had to take on a more prominent role (especially considering that she was the only one of the Bradley sisters to be on the show during its entire run and not be recast) in light of Benaderet's absence.

Supporting characters who suddenly became the lead after the "star" leaves:

I'll give this a shot, 8 Simple Rules might fit this category. Katey Sagal was actually a costar, but the show was focused on John Ritter's character, with his untimely passing she took over as the lead character.

This is an obscure one, My Living Doll. Robert Cummings was the male lead in this series but asked out of his contract, and was released after the 21st episode. The male lead for the remainder of the series (5 episodes) was assumed by Jack Mullaney's character, Peter Robinson.

Jason Bateman in essence, arguably became the "lead" or main focal point on The Hogan Family after Valerie Harper was fired from the show that had previously been her namesake, Valerie.