From 1992 to 1999, Thomas starred along side comedian Tim Allen on the ABC sitcom Home Improvement. Thomas played Tim Taylor's second son, Randy Taylor, but later left the role to focus on academics.
He voiced young Simba in the The Lion King. Archival recordings of his work were used in later Lion King media when young Simba's voice was needed.
He also was the first of three (at their respective times) boys to voice Spot the Dog in the American dub of the British children's series of the same name, the second being Ryan O'Donohue and the third being Haley Joel Osment.
His other Disney related roles included the role of Ben Archer in the 1995 film Man of the House, and Tom Sawyer in the 1995 film, Tom and Huck. As of 2006, he is retired from acting.