| Year | Title | Role | Notes |
| 1985 | Two Fathers' Justice | District Attorney Turpin | Television film |
| 1987 | Hooperman | Reindeer | Episode: "Deck the Cell with Bars of Folly" |
| Bennett Brothers | Richard Bennett | Television film |
| 1988 | My Sister Sam | Lang | Episode: "The Art of Love" |
| Mr. Belvedere | Joe | Episode: "Marsha's Secret" |
| 1989 | Empty Nest | Elton Sexton | Episode: "A Life in the Day" |
| Unsub | Jimmy Bello | 8 episodes |
| 21 Jump Street | Caller (voice) | Episode: "Next Victim" |
| Anything but Love | Bradley | Episode: "Just the Facts, Ma'am" |
| 1990–1991 | Carol & Company | Various characters | 33 episodes |
| 1991 | Princesses | Len Kleckner | Episode: "Someday My Prince Will Gum" |
| The Carol Burnett Show | Various characters | 7 episodes |
| 1992 | Stand By Your Man | Larson | Episode: "Spare Me" |
| Great Scott! | Alberts | Episode: "Choir Mire" |
| 1992–1999, 2019 | Mad About You | Dr. Mark Devanow | 45 episodes |
| 1993 | The Building | The Neurotic Director | Episode: "Father Knows Best" |
| 1993–1995 | The Commish | Alex Beebee | 6 episodes |
| 1994 | The Nanny | Jeffrey Needleman | Episode: "The Playwright" |
| Blue Skies | Kenny | 8 episodes |
| 1995 | A Whole New Ballgame | Dwight Kling | 8 episodes |
| Nowhere Man | Max Webb | Episode: "The Spider Webb" |
| 1996 | Space: Above and Beyond | Colonel Matthew Burke | Episode: "Level of Necessity" |
| Madness of Method | Owen Goodwin | Television short |
| 1996–2002 | Spin City | Paul Lassiter | 125 episodes |
| 1998 | Something So Right | Paul | Episode: "Something About the 'Men' in Menstruation" |
| The Lionhearts | Additional characters (voice) | Episode: "Singin' in the Mane" |
| 1999 | Strangers with Candy | Harry Link, DDS | Episode: "Who Wants Cake?" |
| The Wild Thornberrys | Lyrebird (voice) | Episode: "Koality and Kuantity"[3] |
| America's Funniest Home Videos:Unwrapped for the Holidays" | Himself (host) | Television special |
| 2001 | Even Stevens | Uncle Chuck Stevens | Episode: "Uncle Chuck" |
| The Santa Claus Brothers | Roy Claus (voice) | Television film[3] |
| 2001–2002 | Oswald | Pongo (voice)[3] | 6 episodes |
| 2001–2004 | Lloyd in Space | Vice Principal Feely (voice) | 5 episodes |
| 2002–2003 | Still Standing | Dr. Nathan Gerber | 2 episodes |
| 2002–2021 | Curb Your Enthusiasm | Cousin Andy | 8 episodes |
| 2003 | Just Shoot Me! | Jimmie Korsh | Episode: "The Last Temptation of Elliot" |
| Miss Match | Phil Weston | Episode: "Kate in Ex-tasy" |
| 2003–2004 | Scrubs | Harvey Corman | 4 episodes |
| 2003, 2007 | Kim Possible | Frugal Lucre (voice) | 5 episodes |
| 2004 | Girlfriends | Peter Miller | Episode: "Prophet & Loss" |
| Oliver Beene | Barnaby Rollins | Episode: "X-ray Specs" |
| The Division | Hicks | Episode: "Lost and Found" |
| My Life, Inc. | Dan Mannion | Television film |
| That '70s Show | Kimberly's Dad | Episode: "(I Can't Get No) Satisfaction" |
| Less than Perfect | Lance Corcoran | Episode: "Shoo-In" |
| Father of the Pride | Zebra (voice) | 2 episodes |
| 2004–2008 | Go Baby! | Narrator (voice) | |
| 2005 | Head Cases | Lou Albertini | Episode: "S(elf) Help" |
| Genetically Challenged | Shermie Frankl | Television film |
| E-Ring | Asst. Public Affairs Sec. Danton Murphy | 2 episodes |
| Reba | David | Episode: "Issues" |
| 2005, 2013 | Sesame Street | Fairy Balloon Person, Mr. Disgracey | 2 episodes |
| 2005–present | American Dad! | Al Tuttle (voice) | |
| 2006 | Three Moons Over Milford | Pete Watson | Episode: "Dog Day Aftermoon" |
| Stargate Atlantis | Lucius Lavin | 2 episodes |
| The Angriest Man in Suburbia | Josh | Television film |
| 2007 | Law & Order: Criminal Intent | Ernest Foley | Episode: "Privilege" |
| Psych | Hugo | Episode: "From the Earth to Starbucks" |
| All of Us | Dennis | 2 episodes |
| Two and a Half Men | Artie | Episode: "Is There a Mrs. Waffles?" |
| Sands of Oblivion | Ira | Television film |
| 2009 | Chowder | Gumbo (voice) | Episode: "The Deadly Maze" |
| Dora the Explorer | Greedy King (voice) | Episode: "Dora Saves the Crystal Kingdom" |
| Sherri | Whiny Neighbor | Episode: "Indecision '09" |
| 2009–2011 | The Penguins of Madagascar | Roger (voice) | 6 episodes[3] |
| 2010 | Leverage | Mayor Bradford Culpepper III | 2 episodes |
| Trauma | Ira | Episode: "Frequent Fliers" |
| 'Til Death | Charlie | Episode: "Brother's Keeper" |
| Burn Notice | Marv | 3 episodes |
| 2011 | Harry's Law | Marty Slumach | Episode: "Send in the Clowns" |
| Mr. Sunshine | Rod McDaniel | 2 episodes |
| Femme Fatales | Jonathan Shields | Episode: "Behind Locked Doors, Part 1" |
| Phineas and Ferb | Executive (voice) | Episode: "Perry the Actorpus"[3] |
| 2011–2012 | Luck | Joey Rathburn | 9 episodes |
| 2012 | Sketchy | Lord Arby | Episode: "Downtown Arby's" |
| NYC 22 | Geoff Arnhauldt | Episode: "Thugs and Lovers" |
| 2012–2019 | Law & Order: Special Victims Unit | Various | 4 episodes |
| 2013 | Kroll Show | Mark | Episode: "Can I Finish?" |
| Golden Boy | Paul Daly | 3 episodes |
| Childrens Hospital | Marvin | Episode: "Country Weekend" |
| Drop Dead Diva | Marty Frumm | Episode: "One Shot" |
| Dark Minions | Feldenbaum | Television film |
| The Good Wife | Judge Alan Davies | Episode: "The Next Day" |
| 2014 | The Michael J. Fox Show | Mr. Norwood | Episode: "Secret" |
| Ten X Ten | Man 50s | Miniseries |
| Bad Teacher | Brie's Husband | Episode: "Pilot" |
| Glee | Mr. Rifkin | Episode: "The Back-Up Plan" |
| Sharknado 2: The Second One | Harland 'The Blaster' McGuinness | Television film |
| TripTank | Dad, Stanley (voice) | 2 episodes[3] |
| The Middle | Dr. Niller | Episode: "Unbraceable You" |
| 2014–2015 | Randy Cunningham: 9th Grade Ninja | Mort Weinerman (voice) | 4 episodes |
| 2014–2017 | Red Oaks | Sam Myers | 24 episodes |
| 2014–2019 | Gotham | Mayor Aubrey James | 13 episodes |
| 2015 | What's Your Emergency | Devon Micketty | Episode: "Let's Make a Date" |
| Unbreakable Kimmy Schmidt | Mr. Lefkovitz | Episode: "Kimmy Goes to School!" |
| Love Is Dead | Ken Bell | Television film |
| Happyish | Moses | Episode: "Starring Helen Keller, Moses and Lenny Bruce" |
| Survivor's Remorse | Ira Irwin | Episode: "M.V.P." |
| 2016 | Elementary | Trent Garby | Episode: "A Study in Charlotte" |
| 2016–2017 | Lego Star Wars: The Freemaker Adventures | Imperial Officer General Durpin (voice) | 7 episodes[3] |
| 2017 | Jeff & Some Aliens | Stanley (voice) | 5 episodes[3] |
| Man Seeking Woman | God | Episode: "Blood" |
| Still the King | Walt's Dad | Episode: "Flatbushes" |
| Disjointed | Special Agent Schwartz | Episode: "The Worst" |
| I'm Dying Up Here | Marty Dansak | 5 episodes |
| The Librarians | Bennie Konopka | Episode: "And the Steal of Fortune" |
| 2017–2018 | Elena of Avalor | Cucahute (voice) | 2 episodes[3] |
| 2017–2019 | Welcome to the Wayne | Harvey Timbers (voice)[3] | 5 episodes |
| 2017–2020 | Rapunzel's Tangled Adventure | Uncle Monty (voice)[3] | 10 episodes |
| 2017–2022 | The Goldbergs | Formica Michael Mikowitz | 8 episodes |
| 2017–2025 | Big Mouth | Marty Glouberman (voice) | 42 episodes |
| 2018–2019 | Young Sheldon | Ira Rosenbloom | 3 episodes |
| 2018–2020 | Summer Camp Island | Shark (voice) | 7 episodes[3] |
| 2019 | Documentary Now! | Larry | Episode: "Original Cast Album: Co-Op" |
| Brockmire | Gus Barton | 6 episodes[7] |
| Life in Pieces | Stuart | Episode: "Cabana Hero Action Son" |
| Transparent | Howard | Episode: "Musicale Finale" |
| A Million Little Things | Seymour | Episode: "Austin" |
| John Mulaney & the Sack Lunch Bunch | Himself | Netflix special |
| 2019–2020 | At Home with Amy Sedaris | Sugar Griz / Lenny | 2 episodes |
| 2019–2021 | Last Week Tonight with John Oliver | Richard Sackler / Blobfish | 3 episodes[3] |
| 2019, 2022 | The Good Fight | Judge Alan Davies | 2 episodes |
| 2019–2023 | The Other Two | Skip Schamplin | 5 episodes |
| 2020 | Indebted | Artie | 2 episodes |
| Bob's Burgers | Jules (voice) | Episode: "Flat-Top O' the Morning to Ya" |
| Penny Dreadful: City of Angels | Sam Bloom | Episode: "Dead People Lie Down" |
| Almost Paradise | Uncle Danny | Episode: "Uncle Danny" |
| Helpsters | Land Lovin' Lars | Episode: "Sea Lovin' Sam" |
| The Simpsons | Film Director (voice) | Episode: "A Springfield Summer Christmas for Christmas" |
| 2021 | Mickey Mouse Mixed-Up Adventures | Uncle Manny (voice) | Episode: "Donald's Dilemma" |
| Devil May Care | Meteorologist Smith (voice) | Episode: "The Freeze" |
| Everything's Gonna Be Okay | Toby | 6 episodes |
| Star Trek: Lower Decks | Doopler (voice) | Episode: "An Embarrassment of Dooplers" |
| 2021–2024 | Mickey Mouse Funhouse | Cheezel (voice) | 19 episodes |
| 2022 | Blaze and the Monster Machines | Lord Carburetor (voice) | Episode: "Campfire Stories!" |
| Beavis and Butt-Head | Rabbi (voice) | Episode: "Spiritual Journey" |
| The Watcher | Mitch | 4 episodes |
| Little Demon | Himself (voice) | Episode: "Village of the Found" |
| 2022–2023 | East New York | Captain Stan Yenko | 21 episodes |
| 2023 | History of the World, Part II | Saint Peter | 3 episodes |
| Family Guy | Rabbi Goldstein, Harold Goldfarb (voice) | 2 episodes |
| Ten Year Old Tom | Various characters (voice) | 3 episodes |
| Mr. Monk's Last Case: A Monk Movie | Funeral Director / Twins | Television film |
| 2023–2024 | Hamster & Gretel | Tchotchke Jones (voice) | 2 episodes |
| 2024 | Clone High | Nostradamus (voice) | Episode: "The Cloniest Place on Earth: Missile While You Work" |
| Girls5eva | Himself | Episode: "New York" |
| John Mulaney Presents: Everybody's in LA | Himself (announcer) | 6 episodes[8] |
| Kite Man: Hell Yeah! | Health Inspector (voice) | Episode: "Prison Break, Hell Yeah!" |
| Evil | Judge Jared Jeter | 2 episodes |
| Velma | Himself (voice) | Episode: "This Halloween Needs To Be More Special!"[9] |
| 2024–present | Only Murders in the Building | Vince Fish | 12 episodes[10] |
| 2024–2025 | Night Court | Sy Hoffman | 2 episodes |
| 2025 | Everybody's Live with John Mulaney | Himself (announcer) | 12 episodes |
| The Patrick Star Show | Benjamin B. Nana (voice) | Episode: "Sitcom Stars" |
| Mid-Century Modern | Carol Mintz | 2 episodes |
| Poker Face | Jeffrey | Episode: "Whack-A-Mole" |
| Ad World | Kyle's Dad | Episode: "About Us" |
| Big City Greens |
Ringmaster |
Episode: "Unplanned" |
| 2026 | Krapopolis | Zeus (voice) | Episode: "Weekend at Zeusie's" |
