It's Always Sunny in Philadelphia guest stars

834 actors have guest-starred in It's Always Sunny in Philadelphia across 187 episodes and 18 seasons. The most-credited is Mary Elizabeth Ellis, Waitress in 39 episodes. 354 of them have also guest-starred in five or more of the other shows in this catalogue.

Who came back most

It's Always Sunny in Philadelphia guest actors by episode count
Actor	Character	Eps
Mary Elizabeth Ellis	Waitress	39
David Hornsby	Matthew "Rickety Cricket" Mara	27
Artemis Pebdani	Artemis Dubois	19
Lynne Marie Stewart	Bonnie Kelly	19
Sandy Martin	Mrs. Mac	18
Andrew Friedman	Jack Kelly	13
Lance Barber	Bill Ponderosa	11
Gregory Scott Cummins	Luther McDonald, Donald McDonald, Bill	10
Jimmi Simpson	Liam McPoyle	9
Nate Mooney	Ryan McPoyle	9
Bob Wiltfong	Chet Wallum	8
Brian Unger	The Attorney	7
Catherine Reitman	Maureen Ponderosa	7
Michael Naughton	Waiter, HR Director	7
Travis Schuldt	Ben Smith (The Soldier)	7
T.J. Hoban	Rex	6
Chad L. Coleman	Z	5
Mary Lynn Rajskub	Gail the Snail	5
Thesy Surface	Margaret McPoyle	5
Brittany Daniel	Carmen the Transsexual	4
David Gueriera	Duncan, Host, Thug	4
John Ponzio	Gimp, Jumper, Manager	4
Anne Archer	Barbara Reynolds	3
Carol Kane	Sam	3
Cormac Bluestone	Jimmy Doyle	3

It's Always Sunny in Philadelphia guest stars by season

Guest actors per season of It's Always Sunny in Philadelphia
Season	Guests	Who
Season 1	47	Mary Elizabeth Ellis, Aaron Hartzler, Amy Higgins, Andrew Friedman, Artemis Pebdani, Autumn Reeser, Benton Jennings, Brian McLaughlin, Brittany Daniel, Chris Hendrie, Cormac Bluestone, Dennis Hart and 35 more
Season 2	59	Anne Archer, Lynne Marie Stewart, Mary Elizabeth Ellis, Aisha Hinds, Andy Pessoa, Artemis Pebdani, Bill H. McKenzie, Brian Fitzpatrick, Calvin Tran, Carla Alapont, Carlon Jeffery, Catherine Schreiber and 47 more
Season 3	84	Mary Elizabeth Ellis, David Hornsby, James Price Jr., Jimmi Simpson, John Mariano, Lynne Marie Stewart, Mario Di Donato, Nate Mooney, Sandy Martin, Thesy Surface, Aja Evans, Alex Sol and 72 more
Season 4	68	David Hornsby, Mary Elizabeth Ellis, Artemis Pebdani, Donald Joseph Freeman, Gregory Scott Cummins, Alejandro Patiño, Alexa Demara, Alexandra Sceales-Smith, Atticus Todd, Bill Puluti, Brady Matthews, Cantrell Harris and 56 more
Season 5	49	Artemis Pebdani, Brian Unger, John Ponzio, Lynne Marie Stewart, Mary Elizabeth Ellis, Travis Schuldt, Andrew Friedman, Anna Vocino, Ara Anton, Audra Griffis, Benjamin Koldyke, Brad Carter and 37 more
Season 6	81	Lance Barber, Artemis Pebdani, Brittany Daniel, Catherine Reitman, Chad L. Coleman, Dave Foley, David Gueriera, David Hornsby, Gary Anthony Williams, Johnny Pemberton, Lauren Pennington, Lynne Marie Stewart and 69 more
Season 7	86	Mary Elizabeth Ellis, Catherine Reitman, Cormac Bluestone, David Hornsby, Frances Turner, Ian Reed Kesler, Nick Wechsler, Sasha Roiz, Abe Ruthless, Alanna Ubach, Anise Fuller, Arnold Chun and 74 more
Season 8	53	Alejandro Patiño, Alexandra Daddario, Antonio D. Charity, Artemis Pebdani, Barry Livingston, Brian Unger, Catherine Reitman, Chad Jamian Williams, Cheryl Lynn Bowers, Christopher Carroll, Danielle Parker, David Hornsby and 41 more
Season 9	64	Artemis Pebdani, Mary Elizabeth Ellis, Andrew Friedman, Andrew Thacher, April Scott, Bob Wiltfong, Bonnie Burroughs, Brian Fong, Brian McGovern, Bruce Wexler, Burl Moseley, Burn Gorman and 52 more
Season 10	69	David Hornsby, Lynne Marie Stewart, Michael Naughton, Sandy Martin, Abbey Aziz, Alden Ray, Allison Munn, Amy Holland Pennell, Andrew Leeds, Andrew Ridings, Anna Maria Horsford, Aubrey Morris and 57 more
Season 11	52	Lance Barber, Mary Elizabeth Ellis, Aisha Hinds, Andrew Donnelly, Andrew Friedman, Andy Buckley, Artemis Pebdani, Austin Lyon, Brad Lee Wind, Brian Doyle-Murray, Brian Unger, Brittney Alger and 40 more
Season 12	68	David Hornsby, Wil Garret, A.J. Hudson, Amanda S. Hall, Ammar Daraiseh, Andrew Friedman, Annalisa Cochrane, Anthony Hill, BJ Tanner, Bob Wiltfong, Carter MacIntyre, Casey Sander and 56 more
Season 13	40	Mary Elizabeth Ellis, David Hornsby, Andrew Friedman, Beau Allen, Jason Kelce, Lance Barber, Merrill Reese, Michael Naughton, T.J. Hoban, Travis Schuldt, Aaron Ikeda, Andrew Hawtrey and 28 more
Season 14	44	Bob Wiltfong, David Hornsby, Alex Sanborn, Alexander Leeb, Andrée Vermeulen, Anna Garcia, Atticus Todd, Britt Lower, Bud McGrew, Carlin James, Chad L. Coleman, Christine Horn and 32 more
Season 15	30	Mary Elizabeth Ellis, Colm Meaney, Mark Prendergast, Abigail Bankston, Alixandrée Claire, Artemis Pebdani, Barry Edward O'Rourke, Blake Dang, Brian Huskey, Frank Collison, Geoffrey Owens, Iman Karram and 18 more
Season 16	49	Lynne Marie Stewart, Sandy Martin, Andrew Friedman, Aaron Paul, Aiden Arnold, Alice Kors, Andrew Collins, Andrew Gonzalez, Anthea Neri Best, Artemis Pebdani, Bob Wiltfong, Bryan Cranston and 37 more
Season 17	44	Jesse Palmer, Mary Elizabeth Ellis, Alex Wolff, Andrew Friedman, Artemis Pebdani, Asher Krohn, Audrey Corsa, Audrey Wasilewski, Axel McElhenney, Bob Wiltfong, Brian Unger, Brielle Barbusca and 32 more
Season 18	38	Andrew Friedman, Carol Kane, Gregory Scott Cummins, Sandy Martin, Addison Bowman, Andrew Key, Artemis Pebdani, Bob Wiltfong, Brendan Jennings, Brittany Baker, Cam Gavinski, Charlie Bauer and 26 more

Guest stars you know from somewhere else

The hardest-working character actors in this show's guest cast, ranked by how many other shows in this catalogue they have also guest-starred in. Not the most famous names, the most prolific ones.

It's Always Sunny in Philadelphia guest stars who appear in other shows
Actor	In It's Always Sunny in Philadelphia	Other shows
Tom Virtue	Rink Official	48
Phil Abrams	Doctor	38
Robert Pine	Jack Mara	36
Jack McGee	Detective Lance Girard	34
Van Epperson	Boss	34
Karl T. Wright	Scott	31
Audrey Wasilewski	Nurse	30
Gary Kraus	Dad	30
Casey Sander	Group Leader	29
Jeff Kober	Creepy Guy	29
Barry Livingston	Third Executive	28
Kari Coleman	Margie	28
Patricia Belcher	Judge	28
Peter MacKenzie	Doctor	26
Hugh Holub	Colin Clark (Judge)	26

Played more than one character

It's Always Sunny in Philadelphia actors credited under several characters
Actor	Characters	Eps
John Ponzio	Gimp, Jumper, Manager	4
Gregory Scott Cummins	Luther McDonald, Donald McDonald, Bill	10
David Gueriera	Duncan, Host, Thug	4
Geoffrey Owens	Don Cheadle, Fake Tiger Woods, Middle Age Black Guy (McNabb Imposter)	3
Michael Naughton	Waiter, HR Director	7
Carter MacIntyre	Male Model, Mike	2
Dennis Hart	Construction Worker #2, Fan #2	2
Dennis Hogan	Construction Worker, Fan #1	2
Keith Bullard	Drug Dealer, Scary Guy	2
Leo McElhenney	Bar Kid #3, Water Fountain Kid	2

Shares a cast with

It's Always Sunny in Philadelphia and NCIS — 126 shared actors
It's Always Sunny in Philadelphia and Criminal Minds — 123 shared actors
It's Always Sunny in Philadelphia and ER — 102 shared actors
It's Always Sunny in Philadelphia and CSI: Crime Scene Investigation — 100 shared actors
It's Always Sunny in Philadelphia and Grey's Anatomy — 99 shared actors
It's Always Sunny in Philadelphia and Bones — 83 shared actors
It's Always Sunny in Philadelphia and The Mentalist — 80 shared actors
It's Always Sunny in Philadelphia and NCIS: Los Angeles — 76 shared actors

Cast data from TVmaze, licensed CC BY-SA 4.0.