What is the name of the mouse created by Walt Disney?

The mouse created by Walt Disney is Mickey Mouse.

Mickey was co-created in 1928 by Walt Disney and animator Ub Iwerks. The character emerged after Disney lost the rights to Oswald the Lucky Rabbit, an earlier cartoon star made for Universal. Mickey became the replacement character that anchored Disney's growing animation business.

Mickey's earliest 1928 films were Plane Crazy and The Gallopin' Gaucho, but neither initially found a distributor. His public breakthrough came with Steamboat Willie, released later that year and notable for its synchronized sound. Walt Disney supplied Mickey's voice for many years, helping shape the character's personality.

The name itself was nearly different: Walt reportedly favored Mortimer Mouse before his wife, Lillian Disney, suggested Mickey. Minnie Mouse is Mickey's longtime companion, not the answer to this question; Donald Duck and Goofy are separate Disney characters. Ub Iwerks also deserves credit because he designed much of Mickey's original animated appearance.