Clements made his feature debut as a character animator on "The Rescuers" (1977) and "Pete's Dragon" (1977). In 1981 he became the animation supervisor on "The Fox and the Hound". Future partner John Musker worked as a character animator under him. Clements teamed up with Musker on the ambitious animated flop "The Black Cauldron" (1985). In 1986 he made his directorial debut with Musker and two other collaborators on the feature "The Great Mouse Detective". This feature was based on a pre-Disney short made by Clements.
Together Clements and Musker wrote and directed "The Little Mermaid" (1989), a touching retelling of the Hans Christian Andersen tale. A pivotal film for modern Disney, it brought back critical and commercial clout for feature animation. Moreover it recreated the magical feelings engendered by such Disney classics as "101 Dalmations" (1961), "Lady and the Tramp" (1955) and "Sleeping Beauty" (1959). Clements, along with Musker, wrote, directed and produced "Aladdin" (1992) which featured the music of the late Howard Ashman and Alan Menkin, responsible for the popular music of "The Little Mermaid" (1989), "Beauty and the Beast" (1992) and "Little Shop of Horrors" (1986).