He was one of the original featured cast members on the sketch comedy television series Mad TV, where he stayed for five seasons.

His voice acting roles in animated series include the Sam B of Dead Island as well as title character of Samurai Jack, both John Stewart / Green Lantern and Virgil Hawkins / Static in the DC Animated Universe (across the series Static Shock, Justice League, and Justice League Unlimited), Hermes Conrad in Futurama, Bolbi Stroganofsky in The Adventures of Jimmy Neutron: Boy Genius, Carver Descartes in The Weekenders, Ollie Williams and Judge Dignified Q. Blackman in Family Guy, and Wilt in Foster's Home for Imaginary Friends.

LaMarr has also provided voices for video game franchises including Metal Gear, Jak and Daxter, Darksiders, Final Fantasy, Infamous, Dead Island, Kingdom Hearts, and Mortal Kombat.

Some of the recurring characters LaMarr performed on Mad TV were Desperation Lee ("Funky Walker Dirty Talker"), Jaq the UBS Guy, "sexy player" Rick, talentless R&B singer Savante, and Rocket Revengers star Lieutenant Abraham Jefferson (a.k.a.

He also voices Wilt and other recurring characters in Foster's Home for Imaginary Friends, Carver Descartes on The Weekenders, Philly Phil in Class of 3000, and he portrayed the character Osmosis Jones in the television series Ozzy & Drix (replacing Chris Rock).

[4] In July 2021, LaMarr provided the voice for Orn Free Taa in Star Wars: The Bad Batch.

[5][6] LaMarr's stage credits include The Tempest, As You Like It, Guys and Dolls, Asylum, South Coast Repertory's Make the Break and the Sacred Fools Theater Company's inaugural production of The Fatty Arbuckle Spookhouse Revue.

He appeared in Speaking of Sex starring Bill Murray and Catherine O'Hara, and Back by Midnight with Kirstie Alley, Rodney Dangerfield, and Randy Quaid.

LaMarr made a cameo appearance in the Will Ferrell film Step Brothers, viewing a house for sale with his wife.

LaMarr played Cowboy Curtis in the Los Angeles and Broadway productions of The Pee-wee Herman Show.

[8] He also voiced Sam B, one of the playable characters in Dead Island, and made his debut in the Kingdom Hearts series in Kingdom Hearts 3D: Dream Drop Distance as Phoebus, a character originally from The Hunchback of Notre Dame and voiced by Kevin Kline.

He also provided the voice for multiple roles in Hunt the Truth, a marketing campaign audio-drama for Halo 5: Guardians.

LaMarr had been announced to appear as a regular character in a webisode series, Naught for Hire produced by Jeffrey Berman and Ben Browder (Farscape), that has been in development since 2010.

Voice actors on board were Billy West, Maurice LaMarche, Jim Cummings, Matthew Mercer and Steve Blum.