It was originally planned to make an ongoing series out of this film. Depending on the source, there either would have been two sequels titled "The Fall of the House of Blackenstein" and "Blackenstein III" or one sequel titled "The Black Frankenstein Meets the White Werewolf", the latter of which was intended to be released in 1976. Whichever one of these situations would have been the case, all plans for a series were finally scrapped after this film failed at the box office.
Both the film's director, William A. Levey, and actor John Hart have stated that Joe De Sue was actually a one-time client of the film's producer, Frank R. Saletri, a former criminal lawyer who was trying to break into show business.
According to special effects makeup artist William Munns in an interview conducted for the 2024 Kino Blu-ray edition of The Boogens, the lead actor of Blackenstein, Joe De Sue, was charged with first degree murder. His defence lawyer Frank Saletri, the producer of Blackenstein, got him an acquittal on the charge, so De Sue appeared as the monster in the film to repay the favor. Munns recalled being apprehensive about doing makeup on someone who had been arrested and prosecuted for first degree murder, even if he was acquitted, but ultimately found De Sue to be a gentle, soft-spoken and cooperative person.
Directorial debut for William A. Levey.