Did celebrity impressions on the Howard Stern Show for years.
Did the voice of ZIM in the pilot episode of "Invader ZIM" (2001).
Disliked the Disney Version of Doug.
Due to his role on Futurama, he has portrayed President Richard Nixon more than any other actor.
He moved to Boston, Massachusetts when he was 11.
Is a vegan.
Made his live-action debut in Mark Hamill's Comic Book: The Movie (2004) (V) along with numerous other voice-over actors. Hamill has made a real career as a voice-over actor and wanted many of his peers to appear on film in the flesh.
Provides the voice for "Red" on the M&M commercials.
Some of his characters' voices such as Stimpy are based on the voice of Larry Fine of The Three Stooges.
Turned down the opportunity to reprise his role as the voice of the title character on the "Doug" (1991)-spinoff, "Disney's Doug" (1996) because he considered it a role he did and did well and it was time to put it aside and move on.
Turned down the opportunity to reprise the role as the voice of the legendary Stimpy on John K.'s new "Ren & Stimpy 'Adult Party Cartoon'" (2003) on Spike.