Due to the film's modest budget, Axl Rose donated the use of Guns N' Roses' "Sweet Child O' Mine" free of charge for the final match.
Darren Aronofsky revealed that Mickey Rourke was the first choice to play Randy "The Ram" Robinson but the studio wanted Nicolas Cage. Aronofsky fought to have Rourke as "The Ram", and ultimately won out.
Mickey Rourke actually "blades" (cuts his own forehead with a razor) in this film to add realism to the role. This is also known by the wrestling term as "gigging," "getting color," or "juicing".
The video game Randy and his child neighbor play in both the trailer and the movie was created especially for the film and was fully playable. The game features similar graphics to the original WWF WrestleMania (1989) Nintendo game.
The first scene of Randy working the deli counter was improvised. When real customers kept walking up to the counter during filming, Darren Aronofsky told Mickey Rourke to take their orders while the camera would continue rolling. Also improvised were all of the backstage locker room scenes.
Robert Siegel: The film's writer makes an appearance at the start of the film as a fan getting an autograph from Randy "The Ram" Robinson (Mickey Rourke).
Darren Aronofsky: [angles] This movie features familiar Aronofsky trademarks of the point of view angle and free-held camera.