Stephen King and his wife Tabitha King played a spectator with a loud mouth opinion and a fairly messy face and his wife in the first scene at the fair. King was on the set because he working on the script for Creepshow (1982) with George A. Romero.
Apparently, George A. Romero has stated that the first cut of the movie ran for around a staggering 17 hours.
Director George A. Romero claims that the medieval pre-17th-century Europe tribute organization, the Society for Creative Anachronism, was an influence and inspiration for the movie.
The picture debuted in the year preceding the similarly-titled, popular, yet unrelated television series Supercar (1982). Reportedly, the producers of Knightriders (1981) received a payment so the producers of Supercar (1982) would be able to retain usage and not have to change their TV series title.
Stephen King: As "Hoagie Man," a spectator of the jousting tournament, as he makes a few sarcastic comments during the troupe's first performance while munching on a large sandwich.
Nick Tallo: (who played Jack, the biker with a seltzer bottle in Zombi (1978)) Appears as a bearded customer in a red shirt in the Big Dollar Offer Cafe scene.