Greydon Clark was born on February 7, 1943 in Niles, Michigan. Clark attended Valparaiso University near Chicago and studied acting with coach John Morley. He supported himself as a door-to-door salesman prior to breaking into the movie business.
Clark began his cinematic career as an actor in several features for director Al Adamson. He appeared as the drugged-out biker Acid in Satan's Sadists (for which Greydon also wrote the script under the pseudonym "Dennis Wayne"). Clark also appeared in Hell's Bloody Devils and Dracula vs. Frankenstein for Adamson.
Greydon Clark has directed an array of pictures and straight-to-video offerings from the early 70s up until the late 90s. such as The Bad Bunch, Black Shampoo, Satan's Cheerleaders, Without Warning, Wacko, Joysticks, Uninvited, and Skinheads. In addition to directing, Clark often writes and produces his own movies, and sometimes performs small roles. Greydon both wrote the script and pops up in a minor part in the supernatural revenge film Psychic Killer.
In October 2013, Clark published his autobiography "On the Cheap: My Life in Low Budget Film Making". The book not only covered the production of his films but also documented in significant detail how his films were financed and distributed, including his use of tax shelters to explain how and why the industry produces this kind of film.
- At the beginning of Final Justice, Servo mentions that Greydon Clark was the producer of Hobgoblins. Clark is not listed anywhere in the credits of Hobgoblins, so Servo may be mis-remembering.
- Angels Revenge (Experiment #622 & RiffTrax) - Writer/Director/Brief cameo as a movie director supervising Terry's work
- Final Justice (Experiment #1008 & RiffTrax) - Writer/Producer/Director & as Bob the sheriff
- Star Games (RiffTrax) - Writer/Producer/Director & as Adam
- Uninvited (RiffTrax) - Writer/Producer/Director