For Disney, Thomas Lennon voiced the character Atlas in Hercules: The Animated Series, a landlord in The Legend of Tarzan, Henry in Milo Murphy's Law, Scribble in Tinker Bell and the Legend of the NeverBeast and Secret of the Wings, and Clinton Coot in Legend of the Three Caballeros. He also played Eric Montclare in Out Cold, Freddy Morris in For The People, and Larry Murphy in Herbie: Fully Loaded of which he was also a writer for. He was also a writer for The Pacifier.
Outside of Disney, Lennon is known for his roles as Lieutenant Jim Dangle on the Comedy Central series Reno 911! and as Felix Unger on the CBS comedy sitcom The Odd Couple.