Release of the animated short Steamboat Willie, the first fully synchronized sound cartoon, directed by Walt Disney and Ub Iwerks, featuring the third appearances of cartoon characters Mickey Mouse and Minnie Mouse. This is considered by the Disney corporation to be Mickey's birthday.

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, although both characters appeared several months earlier in a test screening of Plane Crazy. Steamboat Willie was the third of Mickey's films to be produced, but it was the first to be distributed because Walt Disney, having seen The Jazz Singer, had committed himself to produce one of the first fully synchronized sound cartoons.

Steamboat Willie is especially notable for being one of the first cartoons with synchronized sound—the first one was Song Car-tunes by Fleischer Studios in 1924—as well as one the first cartoons to feature a fully post-produced soundtrack, which distinguished it from earlier sound cartoons such as Inkwell Studios' Song Car-Tunes (1924–1926) and Van Beuren Studios' Dinner Time (1928). Disney understood from early on that synchronized sound was the future of film. Steamboat Willie became the most popular cartoon of its day.Music for Steamboat Willie was arranged by Wilfred Jackson and Bert Lewis, and it included the songs "Steamboat Bill", a composition popularized by baritone Arthur Collins during the 1910s, and "Turkey in the Straw", a composition popularized within minstrelsy during the 19th century. The title of the film may be a parody of the Buster Keaton film Steamboat Bill, Jr. (1928), itself a reference to the song by Collins. Walt Disney performed all of the voices in the film, although there is little intelligible dialogue.The film has received wide critical acclaim, not only for introducing one of the world's most popular cartoon characters but for its technical innovation. In 1994, members of the animation field voted Steamboat Willie 13th in the book The 50 Greatest Cartoons, which listed the greatest cartoons of all time. In 1998, the film was selected for preservation in the United States' National Film Registry for being deemed "culturally, historically, or aesthetically significant."