Patrick Swayze had to convince Jennifer Grey to be in this film because she disliked him so much while filming Red Dawn (1984).
Patrick Swayze was offered $6 million to reprise Johnny for a sequel. Swayze wasn't a fan of sequels and turned it down.
Relations between the two main stars varied throughout production. They had already had trouble getting along in their previous project, Red Dawn (1984), and worked things out enough to have an extremely positive screen-test. Still, that initial cooperation soon faded, and they were quickly "facing off" before every scene. There was concern among the production staff that the animosity between the two stars would endanger the filming of the love scenes. To address this, Eleanor Bergstein and Emile Ardolino forced the stars to re-watch their initial screen-tests, the ones with the "breathtaking" chemistry. This had the desired effect, and Patrick Swayze and Jennifer Grey were able to return to the film with renewed energy and enthusiasm.
Patrick Swayze insisted on doing his stunts. During the log scene, he kept on falling off the log and injured his knee so badly he had to have fluid drained from the swelling.
The dancing that Patrick Swayze and Jennifer Grey do during the love scene was the same dance that they did for the screentests. It was not originally supposed to be in the film.