| Television |
| Year | Title | Role | Notes |
| 1985 | The Beachcombers | Leo aka Tall Suit | Season 14, episode 6: "Halibut Stu" |
| 1986 | The Hitchhiker | Maker | Also known as Deadly Nightmares in the United Kingdom; Le Voyageur in France Uncredited Season 3, episode 7: "O.D. Feelin |
| 1988 | 110 Lombard | | TV movie |
| 1989–1999 | Whose Line Is It Anyway? | Himself | UK series, 92 episodes |
| 1990 | It's Garry Shandling's Show | Kenny Tuchman / Bob | Season 4, episode 13: "Chester Gets a Show" |
| 1991 | Who's the Boss? | Bobo the Clown | Season 7, episode 20: "Party Politics" |
| Life As We Know It! | | TV movie |
| 1991–1992 | Parker Lewis Can't Lose | Weather Guy / Clerk / Sweepstakes Guy | 3 episodes Uncredited - 2 episodes |
| 1992 | Say What? | Actor | TV movie |
| 1993–1994 | Mad About You | Boss / Video Vogue Manager | 2 episodes |
| The John Larroquette Show | CIA Agent Kinkaid / Mac / Dave | 3 episodes |
| 1994 | Weird Science | Dale Griffin | Season 2, episode 13: "Unplugged" |
| L.A.X. 2194 | | TV pilot |
| 1995–2004 | The Drew Carey Show | Lewis Kiniski | Main role; 231 episodes Director - Season 5, episode 23: "Kate vs. Speedy" |
| 1996 | Saturday Night Special | — | Creative consultant |
| 1997 | Murphy Brown | Acolyte Monk | Season 9, episode 19: "Desperate Times" |
| 1998–2006, 2013–2024 | Whose Line Is It Anyway? | Himself | US series, 335 episodes Executive producer; 294 episodes |
| 1999 | ABC TGIF | Lewis Kiniski | Segment: "Drew Clues 2" |
| Norm | | Uncredited Season 2, episode 8: "Gambling Man" |
| 2000 | The Cartoon Cartoon Show | Vivian | Voice Episode: "Foe Paws" |
| Buzz Lightyear of Star Command | Professor Spyro Lepton / Von Madman | Voice Episode 37: "Eye of the Tempest" |
| 2001 | Hollywood Squares | Himself / Panelist | 10 episodes |
| Improv All Stars | Himself | TV special |
| Dharma & Greg | Abraham Lincoln | Uncredited Season 4, episode 10: "Dutch Treat" |
| 2002 | Rugrats | Ralph | Voice Season 8, episode 4: "Bow Wow Wedding Vows" |
| 2004–2015 | Two and a Half Men | Dr. Herb Melnick | Recurring role; 30 episodes, Seasons 2, 4–10, 12 |
| 2008 | Reno 911! | Sergeant Clift | Season 5, episode 15: "Undercover Acting Coach" |
| 2009 | Memory Lanes | Ryan Murray | TV movie Writer Producer |
| Bless This Mess | Paul | TV movie |
| 2011 | Working Class | Dr. Edwin Gould DDS | Episode 2: "Dental Claims" |
| Drew Carey's Improv-A-Ganza | Himself | Recurring performer, 34 episodes Producer; 7 episodes |
| 2012 | Are You There, Chelsea? | Jerry | Episode 9: "Fired" |
| 2013 | Bellingham T'Nite | — | TV short Writer Director Executive producer |
| 2019 | American Housewife | Bill Doty | Season 4, episode 3: "Bigger Kids, Bigger Problems" |
| 2020 | Young Sheldon | Dr. Bowers | Season 3, episode 20: "A Baby Tooth and the Egyptian God of Knowledge" |
| 2023 | Ted Lasso | Bruce (voice) | Season 3, episode 10: "International Break" |
| 2025 | Leanne | Bill | Main role13 episodes |