Mortimer Mouse first appeared in Disney’s comic strips as a rival for Mickey, both striving for Minnie’s affections. In 1936 he appeared in a short film called Mickey’s Rival.

There is no official confirmation, just a legend that says that it was Walt Disney himself who was the base for the character’s design. It is said that one of the animators drew a caricature of Disney and he liked it so much that introduced him as a new character. The clues that lead people to believe the legend are Mortimer’s slim and tall figure, thin moustache and the fact that Disney originally wanted Mickey Mouse to have Mortimer’s name.