Thinking about Emmaline Henry's appearance on IDOJ as a magician's assistant and then later as Dr. Bellows wife got me wondering how often an actor appears on a show in a guest role and then later becomes one of the continuing members of the cast in a different role.

How many can you think of?

Harry Morgan won an Emmy for playing a general on M*A*S*H, then later became Colonel Potter. Paul Lynde played Samantha's human driving instructor on Bewitched before becoming warlock Uncle Arthur. Debbe Dunning guest starred on Home Improvement as a random woman at a restaurant who Tim had a hard time not looking at before becoming his assistant Heidi.

Sid Melton played a plumber on an episode of "GREEN ACRES" before playing Alf Monroe.
Bernard Fox played a guy who was an expert on witchcraft in an episode of "BEWITCHED" before playing Dr. Bombay.

Jordan Charney played a one-off role, Mr. Layton, in an episode of "Three's Company" before becoming Jack's boss Mr. Angelino.

Ron Carey appeared as a different character before being cast as Levitt on Barney Miller.

In a reversal, since he co-starred on The Ropers, could we count Jeffrey Tambor's memorable guest-starring role on Three's Company, since the two shows technically count as the same universe and he played a different character?

If I'm not mistaken, Tambor actually portrayed two different characters on different episodes of Three's Company...

Jon Lovitz first played a character named Fred (aka Ulysses S. Grant, 18th President of the United States), a friend Bill makes when he has a quick stay at a mental hospital in season three. In the fourth season, he plays Mike Johnson, a man who threatens to jump off the WNYX building if he's not allowed to speak on the radio, which ends with he and Bill dangling over the edge of the ledge to Dave's office. In season five, Lovitz joins the cast, replacing Phil Hartman, as new anchorman, Max Louis.

Belita Moreno made five guest appearances during the first two seasons of Perfect Strangers as Mrs. Twinkacetti, Larry and Balki's boss's wife. She returns in season three as a cast member named Lydia Markham, a co-worker friend of Larry and Balki.

From "Days of our Lives":

Josh Taylor played Chris Kositchek from 1977-1987 and then he played Roman Brady from 1997-current.

Wayne Northrop played Roman Brady from 1981-1984 & 1991-1994 and then he played Alex North from 2005-2006.

Tamara Braun played Ava Vitali in 2008 & 2015-2017 and then played Taylor Walker in 2011.

Scott Shilstone played Zack Brady on June 8, 2016 and then played Wyatt in 2017 & 2018.

Kyle Lowder played Brady Black from 2000-2005 and he's returning in the role of Rex Brady later this year.

Steve Landesberg was also on as a criminal before coming back as Dietrich.Yes, he played a fake priest.

Does Tim Allen count?

Does Tim Allen count?Did he appear in one show as a guest star then became a regular on that same show in a different role later? If it is Home Improvement and Last Man Standing, those are two separate shows and wouldn't qualify for this thread.

Jack Dodson as an insurance man on TAGS, then later a regular role as Howard Sprague on TAGS/Mayberry RFD.

Did he appear in one show as a guest star then became a regular on that same show in a different role later? If it is Home Improvement and Last Man Standing, those are two separate shows and wouldn't qualify for this thread.

I was thinking of those shows, sorry.

Jon Manfrellotti as a cable guy in season 1 of Everybody Loves Raymond, and later a recurring role as Ray's friend Gianni.

Paul Lynde as a driving instructor in an early Bewitched appearance, and later a recurring role as Uncle Arthur.

This one is kind of iffy: Edgar Buchanan as a one-shot as Captain Jack on the first-produced Leave it to Beaver episode, and later as Uncle Billy. Iffy, because Uncle Billy was talked about often, but had only two appearances.

Ted McGinley played Norman Jablonsky in season 4 of Married With Children before he became Jefferson D'Arcy. It was the episode "It's A Bundyful Life".

Tina Cole: several misc. appearances on My Three Sons, then a starring role in Seasons 8 thru 12 as Katie Miller Douglas.

Jennifer Taylor: several appearances in early seasons of Two and a Half Men, as minor misc. characters, before the recurring role in seasons 6 and 7, as Chelsea.

Donna Reed Show, Episode 5-26 "The Two Doctors Stone" - Bob Crane in a one shot role as Dr. Dave Blevins.

Episode 5-29 "Friends and Neighbors" - Bob Crane in his first appearance in recurring role Dr. Dave Kelsey.

Robert Foulk played Roy Trendall in seasons 2-4 of Green Acres then disappeared and reemerged with a new name as a semi-regular in season 6.

More from Bewitched:

Alice Ghostley in a one-shot role as a klutz maid (ep. 2-17), later in a recurring, different role as Esmeralda.

Bernard Fox in a one-shot role (ep. 2-29), later a recurring role as Dr. Bombay, the witch doctor.

I remember this happening a lot on Perry Mason. Richard Anderson played one character who was on trial for murder before playing Lt. Steve Drumm of the LAPD later on the show's final few seasons.

Paget Brewster appeared on "Community" as IT department staffer Debra Chambers in a Season 5 episode.

She later joined the final season that aired on Yahoo! Screen as consultant Francesca "Frankie" Dart.

Jennifer Taylor: several appearances in early seasons of Two and a Half Men, as minor misc. characters, before the recurring role in seasons 6 and 7, as Chelsea.

Another one from "Two and a Half Men" was Judy Greer.

She played Herb's sister, Myra Melnick, on two eps. of Season 4. She then played Bridget Schmidt, ex-wife of Walden, on Season 9, as well as lesbian Danny.

If I'm not mistaken, Tambor actually portrayed two different characters on different episodes of Three's Company...

Make that three. He played a wealthy man trying to get with Cindy in Season 5, a psychiatrist friend of Terri’s that Jack and Janet thought was a mental patient in Season 6, and finally a dentist in Season 7.

On Happy Days, Linda Purl played one of Richie’s girlfriends in a Season 2 episode, then was Fonzie’s steady girlfriend Ashley in Season 10.

Al Lewis made two guest appearances as different characters on Car 54, Where Are You?, before joining the cast as Officer Leo Schnauser in episode 13.

On Matlock:

- Nancy Stafford played Caryn Thomas in the first season episode "The Seduction" before eventually playing Michelle Thomas from Seasons 2 thru 6

- Before Brynn Thayer portrayed as Leann McIntyre for Seasons 7 & 8(but also played it on the 6th season finale), she played Roxanne Lindmere in the Season 6 episode "The Suspect".

Murder, She Wrote:

Ron Masak made 2 guest appearances as different characters before he got the role of Sheriff Mort Metzger.

William Windom also had a guest role as a different character before he joined the series as Dr. Seth Hazlitt.