Cunningham had worked on other films before Friday the 13th, including the cult horror classic Last House on the Left. Beyond simply producing and directing, it seems he managed every aspect of Friday the 13th; he hand chose the writer, took the initiative to start ad campaigns quickly, picked the release date, found financiers and generally made it his baby from start to finish. I think his passion for the movie is captured in this quote:
"The metaphor that I was using when I was working on the film and afterwards was that of a roller coaster. I was trying to create a roller coaster with hills and valleys. That metaphor works, especially when you watch a film with an audience. Like with a roller coaster, it's a social experience. If you see a horror film in an empty theater, it's just ugly and grim; there's no fun. But if you go with four hundred kids laughing and screaming, it's a different experience"(found here).Not only did this film make bank at the box office with about $40 million in domestic box office receipts, but it continues to be a staple of horror movie viewing. It spawned at least 9 squeals, inspired spoofs, and influenced much of the horror genre since its release. The great monetary wealth this film generated by the film might only be outpaced by the horrifying joy it has brought millions since its release. On this Friday the 13th, we honor Sean S. Cunningham for creating great wealth with his film Friday the 13th.
Friday the 13th on Wiki
Friday the 13th imdb page
Ultraviolent Movie Interview with Cunningham
Cunningham on Wiki
Enjoy the original trailer: