John Morris did not compose the theme song for "Blazing Saddles." The iconic theme song, "Blazing Saddles," was actually composed by Mel Brooks, the director of the film. The lyrics were written by Brooks himself, and the song was performed by Frankie Laine. The humorous and memorable theme perfectly captures the essence of the satirical western film. John Morris, on the other hand, is known for his collaborations with Mel Brooks on other projects, particularly for composing music for several of Brooks' other films, such as "Young Frankenstein" and "Spaceballs."