Based on John Holbrook Vance's novel of the same title, the violence of the book was heavily cut and toned down for television. Much of the more disturbing content of Vance's novel was considered too intense for FCC restrictions.
Originally aired as a Movie of the Week on the ABC network in 1974.
This had a French remake in 1992 & Dimension Films had plans in 2010 to remake this but nothing has come to fruition.
Adam Carolla regularly makes references about this movie on his podcast with many of his guests. He generally pokes fun and makes specific examples of scenes from the movie, which shows he really loves it.
Hanging on the wall of Ronald's bedroom is a Tiki mask figure of a horned devil, a foreshadowing of Ronald's sinister turn. Ronald later paints "The Evil Duke" with devil horns resembling the mask.