| Year | Title | Role | Notes |
| 1989–1990 | 1st & Ten | Vito Del Greco / Johnny Gunn | 11 episodes |
| 1990–1991 | The Fanelli Boys | Frankie Fanelli | 17 episodes |
| 1991–1994 | Dinosaurs | Spike | Voice; recurring role |
| 1993 | The Boys | Doug Kirkfield | 6 episodes |
| Golden Gate | Douglas "BW" Carlino | Unsold pilot |
| 1995 | Hope and Gloria | Billy | Episode: "Love with an Improper Stranger" |
| Misery Loves Company | Mitch | 8 episodes |
| 1996–1997 | NYPD Blue | Jimmy Liery | 5 episodes |
| 1997 | The Last Don | Boz Skannet | Miniseries |
| Leaving L.A. | Reed Sims | 6 episodes |
| Brooklyn South | Joe | 3 episodes |
| 1998 | Homicide: Life on the Street | Bounty Hunter Dennis Knoll | 2 episodes |
| 1998–2003 | Oz | Chris Keller | 38 episodes |
| 1999–2011, 2021–2023, 2025 | Law & Order: Special Victims Unit | Detective Elliot Stabler | 283 episodes |
| 2000–2022 | Law & Order | 3 episodes |
| 2003 | Scrubs | Dr. Dave Norris | Episode: "My White Whale" |
| 2004 | Sesame Street | Himself | Episode: 4065 |
| 2005 | Wonder Showzen | Cooties Spokesman | Episode: "Health" |
| Law & Order: Trial by Jury | Detective Elliot Stabler | Episode: "Day" |
| 2009 | Michael & Michael Have Issues | Himself | Episode: "Greg the Intern" |
| 2010 | Kathy Griffin: My Life on the D-List | Himself | Episode: "Kathy With a Z" |
| 2011 | The Daily Show with Jon Stewart | Tony Bologna | Cameo |
| Ice Loves Coco | Himself |
| 2012 | True Blood | Roman Zimojic | 5 episodes |
| 2013 | Comedy Bang! Bang! | Dr. Phillip Banhauser | Episode: "Aziz Ansari Wears a Charcoal Blazer" |
| 2014 | Veep | Ray Whelans | 2 episodes |
| Surviving Jack | Jack Dunlevy | 8 episodes (including one unaired episode in the United States) |
| 2015 | Drunk History | Othniel Marsh | Episode: "New Jersey" |
| The Jack and Triumph Show | Agent Ryker | Episode: "Siri" |
| Wet Hot American Summer: First Day of Camp | Gene Jenkinson / Jonas Jurgenson | 6 episodes |
| 2016–2017 | Underground | August Pullman | 15 episodes; directed episode: "Auld Acquaintance" |
| 2017 | Wet Hot American Summer: Ten Years Later | Gene Jenkinson | 4 episodes |
| At Home with Amy Sedaris | Ranger Russell | Episode: "Nature" |
| 2017–2019 | Happy! | Nick Sax | 18 episodes |
| 2018 | Pose | Dick Ford | 2 episodes |
| 2019–2022 | American Dad! | Multiple voices | 3 episodes |
| 2019 | The Handmaid's Tale | Commander Winslow | 4 episodes |
| 2019–present | Harley Quinn | Jim Gordon, Two-Face, other voices | 16 episodes |
| 2020 | Family Guy | George Townshend (voice) | Episode: "Short Cuts" |
| Maxxx | Don Wild | 6 episodes |
| The Twilight Zone | Robert | Episode: "A Human Face" |
| Helpsters | Detective Dudley | Episode: "Camper Cortez/Artist Andrew & Detective Dudley" |
| 2022–2022 | Rick and Morty | Multiple voices | 3 episodes |
| 2021–present | Law & Order: Organized Crime | Detective Elliot Stabler | Executive producer |
| 2021 | Bless the Harts | Detective Voccola (voice) | Episode: "Betty's Birthday" |
| 2022 | Solar Opposites | Lonesun (voice) | Episode: “Terry and Korvo Get in a Big Screaming Fight in the Taco Bell Parking Lot” |
| 2023 | Captain Fall | Agent Steel (voice) | 10 episodes |
| Celebrity Jeopardy! | Himself | Contestant |
