Oswald the Lucky Rabbit Mouse cartoon to be filmed was "Plane Crazy" in the summer of 1928, but it was produced as a silent and held back from release. The first Mickey Mouse film with a synchronized soundtrack, "Steamboat Willie", reached the screen that fall and became a major hit, eclipsing Oswald. "Plane Crazy" was later given its own synchronized soundtrack and released on March 17, 1929. Mintz, meanwhile, opened his own studio consisting primarily of former Disney employees, where he continued to produce Oswald cartoons, among them the first Oswald with sound, "Hen Fruit" (1929). While things were going in Mintz's favor, animators
Oswald the Lucky Rabbit studio, started voicing Oswald. When Colvig left the studio in 1931, Mickey Rooney took over the voicing of Oswald until early in the following year. Starting in 1932, Lantz ceased to use a regular voice actor for Oswald, and many studio staff members (including Lantz himself) would take turns in voicing the character over the years. June Foray provided Oswald's voice in "The Egg Cracker Suite", which was the final theatrical short to feature the character. She later voiced him again for an unaired radio pilot, "Sally in Hollywoodland" (1947). Oswald made a cameo appearance in the first animated sequence