John Pomeroy began his animation career working at Walt Disney Productions in 1973. He started out and intended to be a background artist due to his love for painting, but was convinced by mentor Eric Larson to try out character animation and instantly moved into becoming an animator a year later. He would serve as animator on the Winnie the Pooh and Tigger Too segment of The Many Adventures of Winnie the Pooh, The Rescuers, and Pete's Dragon.

Pomeroy would form a bonding friendship with Don Bluth and Gary Goldman. When Bluth directed the animated short The Small One, he assigned Pomeroy to be a directing animator. Pomeroy was animating scenes in The Fox and the Hound when he joined Bluth, Goldman, and eight other members of the animation staff left Disney in 1979. He was apparently in line to have a major role in developing The Black Cauldron before leaving.