Bruce Lee had filmed over 30 minutes of fight scenes for this film when work was suspended to allow Lee to work on Enter the Dragon (1973). However, Lee died before he could return. Six years later, director Robert Clouse fleshed out a feature around the original footage with a new cast, including two stand-ins for Lee, who faces are hidden by dark sunglasses and shadows. Close-ups and stills of Lee's face (including a cardboard cut-out) were also used.
George Lazenby was originally meant to be in this film and was due to meet Bruce Lee on June 20 1973, the day Lee died. For other reasons, Lazenby was not involved in the final project as directed by Robert Clouse.
Chuck Norris was considered for the role of Steiner, but turned it down.
Chuck Norris threatened legal action against Golden Harvest for giving him screen credit for this film. Norris's appearance in the film is archive footage from Meng long guo jiang (1972).
In the film, Bruce Lee's character fakes his own death; the funeral scene includes real footage of Lee's actual funeral.
Bruce Li was offered the role of Bruce Lee's stand-in, but declined.