After dropping out of the University at Boulder, Colorado, Pyle began his career at the Disney studios in 1937 as an office boy, delivering supplies to the animators. He graduated to serving as an assistant animator to Milt Kahl on Pinocchio (1940), Fantasia (1940), and Bambi (1942). Following the animators' strike in 1941, Pyle finished worked on Bambi (1942) before leaving the studio to work for Walter Lantz.
During World War II, Pyle was enlisted to serve in the First Motion Picture Unit film unit at the Hal Roach Studio in Culver City, California, animating training and propaganda films.
Pyle later donated a portion of his archives and papers to the Lilly Library at Indiana University Bloomington.