I have always found this amusing in any tv sitcom in which an actor/actress is used in an episode then later brought back as a completely different character and the fans are not supposed to notice? Is it that the producers, writers, and director think we are that stupid not to notice? Or is it "hey we worked with him/her before lets give em a call for this role" or do they have to audition all over again? Linda Purl is Richies g/f in a few episodes, then in Season 10 Fonz's g/f later on. Do they really think that little of our intelligence that we won't remember anything that has happened previously? Do they watch their own show they create?
Sure, change their clothes and hair to appear different, but people can recognize a face and voice I would think.

Warren Berlinger
Richie's Flip Side (1975) … DJ Charlie The Prince
The Physical (1977) … Army Sgt. Betchler
Hollywood: Part 2 (1977) … Movie Director
The Hucksters (1980) … Mr. Vanburen
It Only Hurts When I Smile (1981) … Dr. Logan DDS in Season 8 Episode 174
http://www.youtube.com/watch?v=Ayu0dRbtBU8

Warren Berlinger was a DJ, Army Srgt. and Fonzies Dentist and perhaps more? Talk about jack of all trades!

Not to mention the whole wardrobe and haircut situation. CLEARLY toward the end of the show, no one was dressing, looking or acting like the 1950s or 1960s any longer.
Don't even get me started about Chuck. 2 different actors, then he vanishes all together, and were not supposed to notice, seriously?

I'm sure there's a few more times they have done this, if anyone knows more recurrences on Happy Days, point them out.

Then you got Ken Lerner used in 3 different episodes, twice as Frankie (as least the same character name but different gangs?) and then he ends up Rocco Baruffi? Rocco was also played by a different actor in s2ep18 Happy Days Richies car.

before she was brought on to play KC, Crystal Bernard played a character named Micki just the season before

...and Lori Beth actually first appeared in an episode as Ralph's date Kim (it was the one where they get locked in the hardware store's basement)

s4ep83 Joanie's Weird Boyfriend is the 1st time we see Derrel as Leroy then
s5ep107 Happy Days "Our Gang" Derrel Maury plays Monk who is a fellow gang member of Fonzies when he was with the Falcons, then he ends up in
s9ep187 Home Movies as a Johnny Suede an arch enemy to the Fonz?

Some TV producers back in the 70s apparently liked to hire the same actors to play different roles throughout the series; it was pretty common in some shows of that era.

Regarding Happy Days...

Warren Berlinger was also in the Season 7 episode "The Hucksters". He was the guy Howard hired to film a commercial for Cunningham Hardware.

There was another actor that played different roles,: he was in the dance marathon episode (Season 4) and in an Season 7 episode. I don't recall his name right now.

Also, Derrel Maury played Chachi's cousin Mario in "Joanie Loves Chachi" (not Happy Days I know, but it's related)

They don't call them character actors for nothing. :)

Also, Derrel Maury played Chachi's cousin Mario in "Joanie Loves Chachi" (not Happy Days I know, but it's related)
There was a cross-over episode, "Life Is More Important Than Show Business," that included Maury as "Mario," so this is valid.

Here's a complete list of credited actors who played two or more different characters:

Alice Nunn

Mrs. Stewart in "A Star Is Bored"
Mama in "Home Movies"

Amy Bosley

Amy in "Fonzie's Hero"
Trick or Treat Girl in "Fonsillectomy"

Andrew L. Paris

Chuck in "Tell-Tale Tart"
Shorty in "You Get What You Pay For"

Arthur Batanides

Eddie in "The Skin Game"
Louie in "The Muckrakers"
The Claw in "The Claw Meets the Fonz"
Eddie in "A Potsie Is Born"
Referee in "Glove Story"

Barbara Treutelaar

Lois in "It Only Hurts When I Smile"
Andrea in "Another Night in Antoine's"

Bob W. Hoffman

Skizzy in "Fonzie Moves In"
Old Man in "A Date with Fonzie"
Middle Aged Man in "Fonzie the Salesman"
Ernie in "Two Angry Men"

Bruce Kimmel

Murf in "Give the Band a Hand"
Mark in "The Howdy Doody Show"

Ceil Cabot

Nun in "Fonzie Loves Pinky" (3)
Teacher in "Graduation" (1)
Mrs. Eckhardt in "Fonzie the Substitute"

Christina Hart

Carole in "Be the First on Your Block"
Carole in "You Go to My Head"
Kitty in "Fonzie the Father"

Clint Howard

Moose in "Bringing Up Spike"
Junior in "Father and Son"

Crystal Bernard

Mikki in "Tell-Tale Tart"
K. C. Cunningham in 15 season-10 episodes

David Ketcham

Coach Pelino in "A Shot in the Dark"
Donald in "Father and Son"
Donald in "Poobah Doo Dah"
Donald in "Fonzie's Spots"

Derrel Maury

Leroy in "Joanie's Weird Boyfriend"
Monk in "Our Gang"
Johnny Suede in "Home Movies"
Mario in "Life is More Important Than Show Business"

Dick Van Patten

Hunsberger in "Fonzie the Salesman"
Mr. Conners in "Graduation"

Gary Epp

Bubba in "They Shoot Fonzies, Don't They?"
Bullfrog in "King Richard's Big Night"
M. P. in "I'm Not at Liberty"

Georganne La Piere

Corrine in "Fish and Fins"
Joy in "Fonzie Versus the She Devils"

Heidi Bohay

Margaret in "Fools Rush In"
Terry in "Home Movies"

Hillary Horan

Peggy in "Spunky Come Home"
Daphne in "Fonzie and Leather Tuscadero" (2)
Elaine in "Welcome to My Nightmare"

Hoke Howell

Sidney in "The Hucksters"
General in "I'm Not at Liberty"

Jack Perkins

Drunk in "Fonzie's Getting Married"
Drunk in "Jailhouse Rock"
Bob in "A.K.A. the Fonz"

James Daughton

Larry in "Wish Upon a Star"
California Kid in "Hollywood"

Jillian Kesner

Patty Petralunga in "Fonzie the Superstar"
Lorraine in "Marion Rebels"

Joe Mays

Mr. Henri in "I Drink, Therefore I Am"
Mr. Mackenzie in "The People Versus the Fonz"

Judy Pioli

Bertha in "Fonzie Versus the She Devils"
Phyllis in "Who Gives a Hootenanny"

Julie Paris

Julie in "Prisoner of Love"
Ann in "Fonzie Moves Out"

Kathi Marshall

Princess in "Haunted"
Kathi in "Fonzie's Hero"
Alison in "Fonsillectomy"
Louise in "The Magic Show"
Sally in "Fools Rush In"
Kathi in "Bride & Gloom"

Kathryn Fuller

Helen Hanley in "Dreams Can Come True"
Mrs. Shellenback in "Vocational Education"
Mrs. Shellenback in "Kiss Me, Teach"

Kathy O'Dare

Mary Lou in "All the Way"
Lois in "Fonzie's New Friend"

Kelly Britt

Gladys in "Joanie's Dilemma"
Woman in "Broadway It's Not"

Ken Lerner

Frankie in "Richie Fights Back"
Frankie in "Fonzie the Flatfoot"
Rocco Baruffi in 8 episodes (seasons 4, 9, 10)

Laurette Spang

Arlene in "Breaking Up Is Hard to Do"
Denise in "Kiss Me Sickly"
Wendy in "Hollywood"

Lew Horn

Officer Marlow in "Richie's Car"
Hinstead in "Hollywood" (1)

Linda Kaye Henning

Lt. Quinlan in "The Physical"
Jean Kelly in "Low Notes"

Linda Purl

Gloria in five season-two episodes
Ashley Pfister in 15 season-10 episodes

Lyle Waggoner

Bobby Burns in "Dreams Can Come True"
Frederick in "Like Mother, Like Daughter"

Lynda Goodfriend

Kim in "Time Capsule"
Kim in "Graduation" (1)
Lori Beth Allen in numerous seasons 5-9 and 11 episodes

Marc McClure

Jimmy Bradkip in "They Shoot Fonzies, Don't They"
Roger in "Joanie's Weird Boyfriend"

Marcia Lewis

Mother Dunbar in "Hard Cover"
Matron in "Marion Goes to Jail"

Marjorie Bennett

Mrs. Harrison in "Guess Who's Coming to Christmas"
The Lady in "Fish and Fins"

Pat Lentz

Emily Sitts in "Dreams Can Come True"
Receptionist in "Not with My Mother, You Don't"

Patricia Wilson

Mrs. Ellis in "Open House"
Paulette Barker in "Marion Rebels"

Peter Hobbs

Doctor in "Fearless Fonzarelli" (2)
Mr. Dugan in "The Book of Records"

Ralph Wilcox

Jason Davis in "Fonzie for the Defense"
Lionel Collins in "Little Baby Cunningham"

Rance Howard

Announcer in "Dance Contest"
Ben Wilson in "Spunkless Spunky"
Mr. Burkhart in "Here Comes the Bride Again"

Ray Girardin

Sgt. Ryan in "The Kissing Bandit"
Big Harold in "Mother and Child Reunion"

Rita Wilson

Roxanne in "A Woman Not Under the Influence"
Barbara McManus in "Where the Guys Are"

Robert Casper

Customer in "Hardware Jungle"
Orville in "Guess Who's Coming to Christmas"

Robin Bach

Waiter in "Another Night at Antoine's"
Maitre d' in "Nervous Romance"

Ronnie Schell

Ernie in "Be the First on Your Block"
Monty Miller in "A Star Is Bored"

Sally Hightower

Sylvia in "Graduation" (1)
Mary Lou in "Fonzie's Baptism"
Melissa in "Be My Valentine"

Scotti Marshall

Cowboy in "Haunted"
Scotti in "Fonzie's Hero"
Patrick in "Fonsillectomy"
Louie in "The Magic Show"
Michael in "Fools Rush In"

Susan Cotton

Miss Radcliff in "Time Capsule"
Librarian in "Hard Cover"

Susan Lawrence

Vivian in "Fonzie Moves In"
Girl #1 in "Fearless Fonzarelli" (2)
Vivian in "Richie Fights Back"
Gigi in "Bringing Up Spike"

Suzanne Wishner

Colette in "A Shot in the Dark"
Vanessa in "Joanie's Dilemma"

Taaffe O'Connell

Carol in "Joanie Busts Out"
Ingrid in "The Hucksters"

Teddi Siddall

Lucille in "Hello, Roger"
Hillary in "Home Movies"
Hillary in "Great Expectations"

Tita Bell

Trudy in four seasons one and two episodes
Harriet in "Nose for News"

Udana Power

Diedre in "Great Expectations"
Louisa in "Fonzie the Father"

Warren Berlinger

Charlie the Prince in "Richie's Flip Side"
Sgt. Betchler in "The Physical"
Director in "Hollywood" (2)
Mr. Vanburen in "The Hucksters"
Dr. Logan in "It Only Hurts When I Smile"

Wayne Morton

Bartender in "Richie Falls in Love"
Dwight Mesmer in "You Get What You Pay For"

anglemark10,
WOW, that is quite a list. I am blown away on how often Happy Days did this! I was working off memory but you have really slam dunked this one. OUTSTANDING!

Thanks. Many, many years ago, I had compiled a list of every guest star that ever appeared on the show. Came in handy for this post, but it did take much, much longer to post than I had anticipated. I didn't realize there were so many people that appeared as different characters.

When I was watching the show during the Ashley era, I didn't even realize Linda Purl had also played Gloria -- even though I'd seen her earlier work in syndication.

I was wondering if the many roles that Frank Adamo played on The Dick Van Dyke Show set a record for the most in a single sitcom? Certainly the most for one that ran relatively few seasons.

This happened a lot back in the '70's. It still happens on shows today too but not as often.

Speaking of recurring actors on a show: I think Dragnet holds the record for most repeat performances by character actors. From what I've read, when Jack Webb liked an actor he would always call them back again and again.

Two other shows in which this has taken place are "Facts of Life" and "Gimme a Break!". The actress that I am referring to is Hazel Shermet. She appeared as two different people on two different episodes of the former and three of the latter. In my opinion, she is quite a lady!