He was born in Canada and began his animation work at Disney and then UPA in the 1940s. He emigrated to Spain and then to England in 1955. In 1958 he produced the work that boosted his career, the BAFTA nominated, The Little Island. After his noted work in the mid-1960s he went on to direct the Academy Award winning A Christmas Carol (1971), the clunker Raggedy Ann & Andy (1977) and the Emmy-winning TVM Ziggy's Gift (1982). He also worked on Who Framed Roger Rabbit (1988) as director of animation and won two more Oscars for his work. He has also written The Animator's Survival Kit (2000).