Clements began his career as an animator for Hanna-Barbera. After a few months there, he was accepted into Disney's Talent Development Program, an animator training ground and workshop. After that, he served a two-year apprenticeship with famed animator Frank Thomas, a supervising animator of Disney films such as Peter Pan (1953), Lady and the Tramp (1955), and The Aristocats (1970).
Clements' career began at Hanna-Barbera. After a brief stint there, he was accepted into Disney's program for aspiring animators. He then spent two years learning from Frank Thomas, a highly respected animator who worked on several famous Disney films like Peter Pan (1953), Lady and the Tramp (1955), and The Aristocats (1970).