Character created by Walt Disney in 1927 for Universal Pictures at the request of "middleman" producer Charles Mintz (who ran his own company, Winkler Pictures). Disney lost creative control of the character after cutting ties with Mintz in 1928, and it prompted him to create Mickey Mouse, a character who would become the mascot of Walt Disney Studios.
Walter Lantz gained creative control of Oswald in 1929 and eventually gained the IP rights to the character some years later. While under Lantz's control, Oswald would sometimes appear alongside characters like Woody Woodpecker. Universal regained control of Oswald when Lantz sold his studio to Universal's parent company at the time, MCA, in 1984 (though Walter Lantz was still the one credited on Oswald-related copyrights).
Oswald's first game appearance was as a non-playable character in Férias Frustradas do Pica Pau. Oswald plays a major role in Epic Mickey, where he resents the popularity of his "brother" of sorts and seeks some form of vengeance.
In order for Disney to use Oswald in Epic Mickey, they traded sportscaster Al Michaels to NBC in exchange for the rights to Oswald and a number of other minor assets.