Black Sheep Hit: "Pinball Wizard" was added to the album as an afterthought, supposedly to gain the favor of New York Times music critic Nik Cohn, who was noted to be a fan of pinball. (Cohn was apprehensive about an early draft of Tommy, but when Pete suggested that Tommy would become famous as a pinball player, his opinion immediately improved.) Pete Townshend even admitted that it was "the most clumsy piece of writing I'd ever done"; he refused to believe there was any merit to it until the producer and the rest of the band said it sounded like a hit.
Breakaway Pop Hit: "Pinball Wizard" served as this for both the original album and the 1975 film.
Executive Meddling: Ken Russell insisted on casting Oliver Reed in the movie, and consequently expanded his character's role to replace that of Tommy's father in the album.
Roger Daltrey was taught real sign language so that he would be able to use it in the gesture song scene in the film. Unfortunately (arguably due to some more Executive Meddling), it ended up just being a parody of sign language instead.
Rod Stewart could've been the Local Lad for the movie. He turned the role down after Elton John advised him not to take it (and after Elton had turned it down himself). Elton later said that Stewart never quite forgave him for that.
Some rumors have gone around about Tiny Tim being considered for that role as well.
David Bowie was considered for the role of the Acid Queen at some point.
The whole thing was originally going to be about a girl who was reincarnated.