Talented actor behind several voices on The Simpsons, including Moe Szyslak, Chief Wiggum, Comic Book Guy, Carl Carlson, and Apu Nahasapeemapetilon. He has also appeared in a number of films including Along Came Polly, Mystery Men, The Smurfs, America's Sweethearts, and Night at the Museum: Battle of the Smithsonian.
He imitated and memorized many scripts, shows, and skits as a child. He studied at Tufts University.
He had a recurring role as a scientist named David on the NBC sitcom Friends. He briefly appeared in the music video for "All Star" by Smash Mouth.
He and Dan Castellaneta have both voiced numerous characters on the long-running series The Simpsons.