Film & TV List | Role | Media |
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| How I Met Your Mother (2005–2012) | Barney Stinson | TV Show |
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| American Reunion (2012) | Celebrity Dance-Off Host | Movie |
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| Adventure Time (2011) | Additional Voices
/
Prince Gumball | TV Show |
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| Batman: The Brave and the Bold (2009–2011) | The Music Meister | TV Show |
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| The Penguins of Madagascar (2010–2011) | Dr. Blowhole | TV Show |
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| The Smurfs (2011) | Patrick Winslow | Movie |
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| Company (2011) | Robert | Movie |
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| Beastly (2011) | Will | Movie |
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| The Best and the Brightest (2010) | Jeff | Movie |
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| Cats & Dogs: The Revenge of Kitty Galore (2010) | Lou (voice) | Movie |
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| Batman: Under the Red Hood (2010) | Nightwing (voice) | Direct to Video |
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| Glee (2010) | Bryan Ryan | TV Show |
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| Yes, Virginia (2009) | Dr. Philip O'Hanlon (voice) | TV Movie |
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| Carrie Underwood: An All-Star Holiday Special (2009) | Ace (voice) | TV Movie |
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| Cloudy with a Chance of Meatballs (2009) | Steve (voice) | Movie |
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| Robot Chicken (2009) | Two-Face | TV Show |
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| Family Guy (2007–2009) | Barney Stinson | TV Show |
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| Sesame Street (2008) | The Fairy Shoeperson | TV Show |
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| Dr. Horrible's Sing-Along Blog (2008) | Dr. Horrible | TV Movie |
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| Harold & Kumar Escape from Guantanamo Bay (2008) | Neil Patrick Harris | Movie |
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| Justice League: The New Frontier (2008) | Barry Allen (voice) (voice) | Direct to Video |
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| Me, Eloise (2006) | n/a | TV Show |
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| The Christmas Blessing (2005) | Nathan Andrews | TV Movie |
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| The Golden Blaze (2005) | The Comic Shop Owner (voice) | Direct to Video |
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| Jack & Bobby (2005) | Prof. Preston Phelps | TV Show |
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| Numb3rs (2005) | Ethan Burdick | TV Show |
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| Law & Order: Criminal Intent (2004) | John Tagman | TV Show |
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| Harold & Kumar Go to White Castle (2004) | Neil Patrick Harris | Movie |
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| Spider-Man (2003) | Peter Parker | TV Show |
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| Boomtown (2003) | Peter Corman | TV Show |
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| Undercover Brother (2002) | Lance | Movie |
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| Justice League (2002) | Ray Thompson | TV Show |
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| The Mesmerist (2002) | Benjamin | Movie |
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| Touched by an Angel (2002) | Jonas | TV Show |
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| Ed (2001) | Joe Baxter | TV Show |
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| Sweeney Todd: The Demon Barber of Fleet Street in Concert (2001) | Tobias Ragg | TV Movie |
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| The Wedding Dress (2001) | Travis Cleveland | TV Movie |
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| The Legend of Tarzan (2001) | Moyo | TV Show |
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| As Told by Ginger (2001) | Ned | TV Show |
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| Son of the Beach (2001) | Loverboy | TV Show |
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| Static Shock (2001) | Johnny Morrow
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Replay | TV Show |
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| Stark Raving Mad (1999–2000) | Henry McNeeley | TV Show |
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| Will & Grace (2000) | Bill | TV Show |
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| The Next Best Thing (2000) | David | Movie |
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| Joan of Arc (1999) | The Dauphin, later King Charles VII of France | TV Movie |
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| The Christmas Wish (1998) | Will Martin | TV Movie |
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| The Proposition (1998) | Roger Martin | Movie |
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| Starship Troopers (1997) | Carl Jenkins | Movie |
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| Homicide: Life on the Street (1997) | Alan Schack | TV Show |
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| The Outer Limits (1996) | Howie Morrison | TV Show |
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| Legacy of Sin: The William Coit Story (1995) | William Coit | TV Movie |
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| My Antonia (1995) | Jimmy Burden | TV Movie |
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| Not Our Son (1995) | Paul Kenneth Keller | TV Movie |
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| Animal Room (1995) | Arnold Mosk | Movie |
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| The Man in the Attic (1995) | Edward Broder | TV Movie |
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| Capitol Critters (1992–1995) | Max | TV Show |
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| Snowbound: The Jim and Jennifer Stolpa Story (1994) | Jim Stolpa | TV Movie |
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| A Family Torn Apart (1993) | Brian Hannigan | TV Movie |
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| Murder, She Wrote (1993) | Tommy Remsen | TV Show |
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| Doogie Howser, M.D. (1989–1993) | Dr. Doogie Howser | TV Show |
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| Quantum Leap (1993) | Mike Hammond | TV Show |
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| Captain Planet and the Planeteers (1992) | Todd Andrews | TV Show |
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| Blossom (1991) | The 'Charming' Derek Slade | TV Show |
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| Stranger in the Family (1991) | Steve Thompson | TV Movie |
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| Cold Sassy Tree (1989) | Will Tweedy | TV Movie |
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| B.L. Stryker (1989) | n/a | TV Show |
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| Home Fires Burning (1989) | Lonnie Tibbetts | TV Movie |
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| Purple People Eater (1988) | Billy Johnson | Movie |
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| Too Good to Be True (1988) | Danny Harland | TV Movie |
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| Clara's Heart (1988) | David Hart | Movie |
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Film & TV List | Role | Media |
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| Conan (2011–2012) | Himself | TV Show |
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| Late Show with David Letterman (1994–2012) | Himself
/
Himself - Guest
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Himself - Top Ten List Presenter | TV Show |
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| The Talk (2010–2012) | Himself
/
Himself - Guest | TV Show |
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| A Very Harold & Kumar 3D Christmas (2011) | Himself | Movie |
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| The Muppets (2011) | Himself | Movie |
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| The Late Late Show with Craig Ferguson (2005–2011) | Himself
/
Himself - Excerpt Reader
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Himself - Guest | TV Show |
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| Late Night with Jimmy Fallon (2009–2011) | Himself
/
Himself - Guest | TV Show |
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| Watch What Happens: Live (2010–2011) | Himself
/
Himself - Guest | TV Show |
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| The Daily Show with Jon Stewart (2000–2011) | Himself | TV Show |
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| The Tonight Show with Jay Leno (1992–2011) | Himself | TV Show |
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| Entertainment Tonight (2007–2010) | Himself | TV Show |
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| The View (2005–2010) | Himself | TV Show |
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| The Oprah Winfrey Show (2010) | Himself | TV Show |
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| The Tonight Show with Conan O'Brien (2009) | Himself | TV Show |
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| Top Chef Masters (2009) | Himself | TV Show |
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| The Early Show (2009) | Himself | TV Show |
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| Saturday Night Live (2009) | Himself - Host
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Various | TV Show |
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| Late Night with Conan O'Brien (2006–2008) | Himself | TV Show |
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| Big Brother (2006) | Himself | TV Show |
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| Celebrity Poker Showdown (2004) | Himself | TV Show |
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| Last Call with Carson Daly (2004) | Himself | TV Show |
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| The Simpsons (1991) | Himself | TV Show |
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| Good Morning America (1989–1990) | Himself | TV Show |
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