Jake the cat was played by two different Abyssinian cats: Rumple and his sister, Amber.
Ronnie Schell, who provided the voice of the title feline, was also given the small part of an army sergeant. In post-production, it was decided that his voice was too easily recognizable, so the on-screen role was re-dubbed by another, unidentified and anonymous actor.
Harry Morgan plays an eccentric general and McLean Stevenson plays a harried doctor. In Harry Morgan's first appearance on M*A*S*H (1972), he played an eccentric general; McLean Stevenson was a regular in the role of the harried doctor in command of the 4077th.
This is the last Disney film to involve actor Hans Conried. The arguably best known role of his career was that of Captain Hook/George Darling in Peter Pan (1953).