(written from a Production point of view)
A lifelong animator, Fennell began his career working, uncredited, on Disney short films including Mickey’s Mellerdrammer (1933), Mickey’s Mechanical Man (1933), and Father’s Noah’s Ark (1933). 
Fennell notably directed a pair of 1941 animated shorts, each titled This Changing World designed to update Americans on the unfolding events of World War II (prior to the United States entering the war). 
In the 1960s, Fennell wrote, directed and produced fifty-two episodes of Bozo: The World's Most Famous Clown
Fennell worked in the art department on a number of animated television series in the 1970s and 1980s including Sabrina and the Groovie Goolies, Fat Albert and the Cosby Kids, Tarzan, Lord of the Jungle, Flash Gordon, and The New Adventures of Zorro.