George has done voiceover work in animated shows such as Batman: The Animated Series (as musician turned gangster Jimmy "The Jazzman" Peake); Handy Manny; Kim Possible as antagonist Duff Killigan, a Scotsman who uses exploding golf balls when attacking Kim and Ron Stoppable, Kim's sidekick; Avatar: The Last Airbender as Guru Pathik; Batman Beyond; Justice League (voicing Parasite, in a style similar to the first voice actor of Parasite, Brion James), Morgan Edge and President George W. Bush), MASK, Invader Zim, and Jedi Master Ki-Adi Mundi in Season 2 of Star Wars: The Clone Wars. He has also appeared in video games like Star Wars: Knights of the Old Republic, Baldur's Gate, Ultimate Spider-Man, Mass Effect 3, EverQuest II and Final Fantasy XIV.