In 2009, 11 years after this film's release, Todd Solondz wrote and directed Life During Wartime (2009), which is a sequel to this film. However, every returning character in the sequel was played by a different actor.
This film was ranked number 19 on Premiere Magazine's list of "The 25 Most Dangerous Movies".
Sundance Film Festival refused to screen the film.
Dylan Baker did not learn that the name of the film was Happiness until it was screened at the Toronto International Film Festival in 1998. He said it was known to him only as "The Todd Solondz Untitled Project", and was shocked at the choice of title. He said, however, that when he finally saw the finished film, he understood, and said, "How could it be called anything but Happiness?".
When the film was originally submitted to the MPAA, it was given the NC-17 rating, causing October Films, the original distributor who was owned by Universal Pictures at the time, to sell it to the independent Good Machine Productions, who released the film unrated.