Steamboat Willie (1928)

Steamboat Willie is a 1928 American animated short film directed by Walt Disney and Ub Iwerks. It was produced in black-and-white by Walt Disney Studios and was released by Celebrity Productions. The cartoon is considered the debut of Mickey Mouse, and his girlfriend Minnie, despite both the characters appearing several months earlier in a test screening of Plane Crazy. Steamboat Willie was the third of Mickey's films to be produced, but was the first to be distributed.

More at Wikipedia.