According to an interview with bit-part actor Jeff Pang (who plays himself), many of the party scenes in the film were completely unscripted. The cameras would roll and the "kids" would just get drunk, get high, and play around. There is debate however, as to whether the 'blunt-rolling tutorial' scene in Washington Square Park used real marijuana or not.
The film received an NC-17 rating from the MPAA (no one 17 and under admitted). Clark unsuccessfully appealed the rating but the MPAA recommend that Clark not cut the film because they felt it would lose some of its impact.
Justin Pierce (Casper) broke his wrist in a fight with a club bouncer during production. During the night pool scene he is seen holding his broken, wrist above his head to limit the pain as he could not get a cast put on it until after filming.
The film follows Harmony Korine's script quite closely. There is really only one notable difference: the removal of a scene that visually represents an apocryphal story told by Telly in which Casper, as a young child, mistakes his parents' S & M lovemaking for a real attack and stabs his leather-masked father to death with the family's turkey-carving knife.
The British Board of Film Classification insisted on 40 seconds being cut from the scene when a small boy wakes up on a sofa to find a girl being raped several feet away. This is due to British law that does not allow for a child to be in the same scene as simulated sex.
After this movie, Leo Fitzpatrick decided he didn't like acting and quit. He took US$300, his skateboard, and some clothes and moved to Britain. After a three-year hiatus, Leo was convinced to come and make a follow-up to the film.
The film was given an NC-17 rating in the United States, which caused controversy at Miramax Films, whose parent company is The Walt Disney Company. Disney forbids the release of films rated NC-17. Alarmed by this, Miramax heads Bob Weinstein and Harvey Weinstein came up with a simple solution: they made a one-off independent distribution company, Shining Excalibur Pictures, which handled the films distribution. (The film was later released in the United States without a rating.) A similar situation happened with the Weinsteins for the release of the film Fahrenheit 9/11 (2004).
The movie was actually cast long before financing was pulled together. Many were selected from Harmony Korine's own group of friends, who were, incidentally, the basis for some of the script's characters. In the year or so it took to secure investors the initial cast crop had either aged considerably or, after more thought, been replaced.
Mia Kirshner was originally cast as Jennie. Chloë Sevigny, at that stage, had a minor role as one of the girls in the swimming pool, even though Harmony Korine said the character was inspired by her. And only a couple of days before production began, Sevigny was asked to take on the role of Jennie. Mia Kirshner, too, actually went on to achieve some level of success, however did not end up starring in the film.
"Natural One" was a surprise hit by the band Folk Implosion from the Kids soundtrack, reaching #29 on the Billboard Hot 100 Singles chart. The song is not featured in the film but is part of the soundtrack alongside additional instrumental tracks by Folk Implosion that plays during the film. Folk Implosion was a side project of Lou Barlow, better known for playing in bands Dinosaur Jr. and Sebadoh.