Motown Productions bought the rights to the stage show with the intent of having Stephanie Mills reprise the role of Dorothy. However, Diana Ross lobbied intensely for the role. Despite the fact that everyone (including Motown head and former lover Berry Gordy) believed that she, being 13 years older than Mills, was too old, she insisted that the role of Dorothy was ageless. She also said she would be able to guarantee Michael Jackson as the Scarecrow if she was cast.
Original director John Badham was fired when he objected to Diana Ross, then 33 years old, being cast as the 14-year-old Dorothy. Though in the movie her role was changed to a 24-year-old kindergarten school teacher.
The first song that Michael Jackson sings, "You Can't Win," was originally written for the stage version for the Winkies to sing to Dorothy about the futility of escaping from Evillene. The song was cut from the stage version of the musical during previews but was included in the film as the Scarecrow's song.
In his book "Making Movies," Sidney Lumet admits that the filming of the Emerald City Sequence on the plaza at the World Trade Center had to be cut short because of wind and scheduling. The Port Authority would not allow more time to fix the mistakes, the red sequence had to be shortened due to a lighting error, and there was no time to re-shoot.
The scene in which the Cowardly Lion emerges from one of the statues in front of the main research branch of the New York Public Library was shot on a set instead of the actual location because it was logistically impossible to film an entire scene devoid of people, save the main actors, without traffic and pedestrians getting in the way of the production.
The original New York production of "The Wiz" opened at the Majestic Theater on January 5, 1975, starring Stephanie Mills, ran for 1,672 performances and won the 1975 Tony Awards for the Best Musical and Score and was nominated for Best Book.
Simultaneously with the release of the film, Congoleum, the flooring company that designed the look of the Yellow Brick Road for the film, also marketed the same design (also called Yellow Brick Road) for home use.
Joel Schumacher's script for The Wiz was influenced by Werner Erhard's teachings and his Erhard Seminars Training ("est") movement, as both Schumacher and Diana Ross were proponents. The speech delivered by Glinda the Good Witch at the end of the film, and the song "Believe in Yourself", are particularly laden with est-ian concepts.