Stephen King was quite impressed with Kathy Bates' performance in this film, so much so that he later wrote two more roles for her. The title role in his novel "Dolores Claiborne" was written with Bates in mind, and Bates later starred in the film adaption of Dolores Claiborne (1995). King also wrote the script for the TV mini-series The Stand (1994). His original novel featured a (male) character named Ray Flowers; upon hearing that Bates wanted to be involved in the miniseries, King re-wrote the part as a woman (Rae Flowers) just so Bates could play the part (uncredited).
James Caan once showed up to the set hungover, and all of the scenes he shot that day were unusable. Rob Reiner told Caan he had to do the scenes again because there was "a problem at the lab." When Caan learned it had nothing to do with labs, he offered to cover the money he lost the studio.
Annie Wilkes is Stephen King's favorite written character, because she was always surprising to write, with unexpected depth and sympathy.
Jack Nicholson was offered the role of Paul Sheldon, but passed because he was not sure he wanted to do another movie based on one of Stephen King's novels, after what he had experienced with Stanley Kubrick on The Shining (1980).
One of Stephen King's first typewriters had a malfunctioning "N" key, just like the one used by Paul in the movie. In the novel, the typewriter also drops its "T" and "E" keys. Those two letters are second and first most commonly used letters in the English language, respectively, making Paul's job even tougher.