One of the original cast members on the sketch comedy series Mad TV, he is also known for his voice acting on the animated series Futurama as Hermes Conrad and about a million minor recurring characters and background voices, Static Shock as Virgil "Static" Hawkins, the title character of Samurai Jack, Judge Brown and Blacku-weather meteorologist Ollie Williams in Family Guy, Green Lantern John Stewart in Justice League and Justice League Unlimited, Wilt in Foster's Home for Imaginary Friends, Carver Descartes in The Weekenders, Reddas in Final Fantasy XII, and Vamp in Metal Gear Solid 2 & 4. And according to one source "Evil Barack Obama" in Make My Video C+C Music Factory. He replaced Chris Rock's role, Osmosis Jones, from the film for the short-lived television series Ozzy and Drix. He also had a minor role in Pulp Fiction, playing the character who was the Trope Namer for I Just Shot Marvin in the Face.
He has a very versatile voice range.