Thomas has had a long career doing voices for animation including "Animaniacs", "Duckman", "CatDog", "The Adventures of Tarzan", "Justice League of America" and multiple roles on "The Simpsons," "King of the Hill" and "Family Guy". In 2005, he had a guest stint as Charlize Theron's "Uncle Trevor" on Fox's "Arrested Development". In 2006, he reprised his voice role in "Brother Bear 2" and appeared as himself in the feature film "The Aristocrats". He began production on "ArnoldSpeaks.com", a video blog, as the voice of Arnold Schwarzenegger; Animax Entertainment won an Emmy for a broadband animated series produced for ESPN, "Off Mikes".