Walt is said to have drawn the first sketches of Mickey Mouse on a train to Los Angeles after losing the rights to Oswald, the cartoon rabbit. Viewed from a distance of over 70 years, it appears that Mickey's success was inevitable, that he was a kind of force of nature in entertainment, destined to become one of the most beloved characters in the world. But the truth isn't so simple. In fact, Mickey Mouse could easily have become just another character in the history of animation, joining the likes of Popeye, Betty Boop, and Felix the Cat. In fact, when Mickey was first created he didn't look so very different from many of his predecessors. Clearly, the most significant factor that led to Mickey's super-stardom was his optimistic, cheerful, resilient character -- one very much like Walt's. It may be true that animator Ub Iwerks was largely responsible for Mickey's final form -- reworking Walt's sketches to make the mouse easier to animate. But as old animators have commented, according to animation historian Charles Solomon, "Ub designed Mickey's physical appearance, but Walt gave him his soul."

Still, an appealing personality didn't guarantee Mickey fame. He got his first big break because of one seemingly simple flash of inspiration: In a day when cartoon characters were silent, Walt decided to give Mickey Mouse a voice. Other studios had experimented with synchronizing sound and animation, but none had done a particularly successful job. Writes Solomon of Mickey's start, "The first three films . . . were made as silents. Distributors expressed little interest in them: Mickey seemed very similar to Oswald. Disney was asking for $3,000 per film (a considerable sum at the time) and insisted on retaining the rights to the Mickey Mouse character." It was then that Walt decided to spend every dollar he had creating a soundtrack for one of these three cartoons, "Steamboat Willie." It wasn't easy, and a lesser man than Walt would have given up. Musicians didn't keep time to the cartoon . . . a bull-fiddle player turned up drunk . . . money ran short. But the job was finally done. And when "Steamboat Willie" premiered at New York's Colony Theater, it attracted a great deal of attention. The "New York Times" called it "an ingenious piece of work with a good deal of fun." And Mickey was off and running.