Wells began his film career by joining Richard Williams Animation, where he served as a supervising animator on Who Framed Roger Rabbit. After the closing of Richard Williams Animation, Wells became a member of Amblimation, a studio owned by Steven SpielbergSteven Spielberg, where he served as director on their only three films: An American Tail: Fievel Goes West, We're Back! A Dinosaur's Story and Balto. Wells was set to direct a sequel to Casper, but the project was cancelled.
After the closing of Amblimation, Wells joined Disney, PixarPixar and Universal where he worked as storyboard artist on many animated projects, and also directed The Prince of Egypt which was nominated for an Annie Award.