At the end of the film, T.T. Rodriguez and his brothers' sign for the nightclub is misspelled as Rodriquez. This joke wasn't planned in advance. Paul Thomas Anderson misspelled Rodriguez in the screenplay and decided to make the scene funny.
After seeing a rough cut of the film, Burt Reynolds regretted making it and fired his agent for recommending the role to him. Reynolds ended up winning a Golden Globe and being nominated for an Academy Award for his performance.
Leonardo DiCaprio was originally offered the role of Dirk Diggler. He liked the screenplay, but turned it down because he had already signed on to do Titanic (1997). DiCaprio suggested Mark Wahlberg for the role.
Before the film was finished, director Paul Thomas Anderson sent a rough copy to New Line Cinema for the film's trailer. The movie was pirated and distributed before the official release. The pirated print includes many scenes not in the movie or DVD deleted scenes. Some were very explicit, and may have been deleted to avoid an NC-17 rating.
In a deleted scene, Dirk Diggler crashes his Corvette into a telephone booth. The scene was deleted because of time, but the car still remains wrecked when Dirk visits Rahad Jackson's house, drives away, and drives back to Jack's house. When Dirk and Reed are conspiring to rob Rahad's house, Dirk says, "That'll be enough to get the 'Vette fixed."
According to William H. Macy, the scene where Dirk Diggler wins the Golden Phallus Award was filmed with about 100 extras who had shown up in their own 1970s clothes. They weren't told what kind of movie they were in, only that it was a film featuring Burt Reynolds. The crowd was told to applaud after Melora Walters had announced Diggler as the winner. However, after Walters added some explicit sexual profanity to her line, there was a stunned silence. Subsequently, about half of the extras got up and left the set, not to return again. This caused some delay in filming, in order to reassemble another crowd of extras, so when they finally resumed filming, director Paul Thomas Anderson took great care to explain to the new crowd what they were in for.
Electric Light Orchestra leader Jeff Lynne originally refused to let the song "Livin' Thing" be used in the film because he has "a problem with sex and violence in movies". Lynne asked to see a screening of the film and loved it so much that he allowed the song to be used.
According to an interview with Paul Thomas Anderson, he and Burt Reynolds did not get along during filming. Anderson still planned to hire Reynolds for Magnolia (1999), but Reynolds became angry with Anderson during the film's promotional tour and turned the role down.
Many 1970s porn stars and porn directors and producers criticized the film, saying it was inaccurate for the popularity Dirk achieved, and that filming porn was illegal in the late 1970s. One exception was Paul Thomas, a longtime adult film star who became the most successful and respected director in the business, on projects for Vivid Video. He judged the film "pretty accurate" outside of some general details.
Burt Reynolds said in a Maxim magazine interview that he researched his role by visiting porn sets and talking with real porn actors. He said the experience made him want to wear rubber gloves and take a shower afterward, and all the porn actors asked him how to get a Screen Actors Guild card.
The sequence where Dirk, Reed, and Todd are at Rahad Jackson's house, an attempted scam involving drugs, a rich and violent man, and a robbery plot that turns into a scene of bloodshed, is a reference to the Wonderland murders that centered around John Holmes and gangster Eddie Nash.
Although the movie's title is the same as the 1977 disco hit by Heatwave, the group's lead singer, Johnny Wilder Jr., a devout born-again Christian, refused to allow the song in the movie because it was about dancing, not pornography.
Dirk's first character is named John, a reference to real-life porn legend John Holmes, upon whom Dirk's character was based. Dirk mentioned that he had just came back from the Marines; Holmes spent some time in the Army.
Dirk Diggler's habit of preparing for his scenes in the bathroom is based on John Holmes, who said he liked to rehearse in bathrooms because "it's usually the only room in the house that has a lock on the door".
Burt Reynolds hated the idea of doing a movie promoting the porn industry and turned the Jack Horner role down seven times. He also felt like he was selling out and letting his old fans down. After angrily telling Paul Thomas Anderson the last time offered he wasn't interested and to leave him alone, Anderson told him if he could carry that attitude with him to the role, he would be nominated for an Oscar. He subsequently chose to do the film and was nominated for a Best Supporting Actor Oscar.
When Floyd Gondoli tries to pitch Jack on changing to video, The Colonel is laughing in the back of the shot. He starts right when Floyd describes his sexual turn-ons. Paul Thomas Anderson blurred the shot.
When Dirk Diggler proposes the idea of a serial porn detective story to Jack, Dirk says, "I don't want to do stuff like Holmes is doing with his Johnny Wadd character, hitting women and stuff. That just ain't right." This leads the viewer to believe that Dirk and Holmes are rivals in the industry, not that Dirk is a direct representation of Holmes.
When Buck is talking to the customer in the Hi Fi Store he mentions an upgrade on the stereo called TK421. TK421 is also the guards identification number in Star Wars: Episode IV - A New Hope (1977) when the Millenium Falcon has been captured by the Death Star. Han Solo lures the Storm Trooper on board by asking for help.
The entire film is based on the short film The Dirk Diggler Story (1988), also by Paul Thomas Anderson. It was a This Is Spinal Tap (1984)-like mockumentary, which would go on to be redone for the short "Dirk Diggler Story" in this film. In the original short film, Robert Ridgely, who plays The Colonel here, played Jack Horner. The man with whom Don Cheadle is talking in the stereo store is Michael Stein, who played Dirk Diggler. The original script was 300 pages, cut down to 180 pages.
Paul Thomas Anderson used Exhausted: John C. Holmes, the Real Story (1981), a documentary about John Holmes, as a reference for some of the scenes in this film. Many interview scenes, including one where a strung-out Dirk tells the interviewer about how Jack allows him to block and edit his own sex scenes, are identical to the interviews in "Exhausted", especially one where a strung-out John Holmes, for no clear reason, lies about how director Bob Chinn allows him to block his own sex scenes.
The donut shop where Buck Swope encounters the robbery is Miss Donuts on Sherman Way between Lindley Ave. and Reseda Blvd. Further down the street is a church that used to be a boxing ring and rock club. The nightclub exterior scenes were filmed there. The Reseda Theatre, the nightclub, the church, the dirt parking lot, the donut shop, and the storefront where the kid gets beaten up are all on Sherman Way between Reseda and Lindley.
Set between 1977 and 1984. Among other things, Jack Horner calls Buck and Jessie's baby "an Olympic swimmer", and Dirk Diggler's outfit in the final scene is identical to the kind of clothes that Don Johnson wore on Miami Vice (1984).
While doing interviews to promote his memoir "But Enough About Me," actor Burt Reynolds said that he will probably never work with Paul Thomas Anderson again because, as he told GQ, "Personality-wise, we didn't fit. (...) I think mostly because he was young and full of himself. (...) Every shot we did, it was like the first time [that shot had ever been done]. I remember the first shot we did in Boogie Nights (1997), where I drive the car to Grauman's Theater. After [that] he said, 'Isn't that amazing?' And I named five pictures that had the same kind of shot. It wasn't original. But if you have to steal, steal from the best." Reynolds further claimed that Anderson offered him a part in Magnolia (1999), which he turned down. "I'd done my picture with Paul Thomas Anderson, that was enough for me," Reynolds said. 
The character Buck Swope is a nod to Putney Swope (1969), a film by Robert Downey Sr. who played Burt in the film. That film was a satire on the New York Madison Avenue advertising world, where an African American was appointed President of an ad company,
Jack Horner tells Kurt, 'Switch the title card, I want it to come flying right out of the screen, right at the audience!' and Kurt replies 'Nice! Piece of cake!' Kurt is played by Ricky Jay, an expert at magic and card tricks who makes playing cards fly across a stage with speed and accuracy.
Dirk and Reed record "You Got the Touch" at Sound City Studios in Van Nuys. This is the same studio where Rick Springfield recorded "Jessie's Girl" - later heard during the drug deal scene on Rahad's mix tape.
Paul Thomas Anderson: [long take] The opening scene is three minutes long, taken in a single camera shot, beginning in the street where Jack Horner and Amber Waves drive up and following them as they get out of the car and walk into a nightclub. Most of the characters are introduced in that shot.
The trivia items below may give away important plot points.
William H. Macy's character is loosely based on porn actor Cal Jammer, whose girlfriend Jill Kelly was having a secret relationship with actress P.J. Sparxx and another with a male porn actor. Jammer later shot himself in the head on Kelly's front lawn.
Paul Thomas Anderson originally included a sequence where Becky Barnett's new husband beat her up, and she called Dirk Diggler for help. Dirk said he would meet her, but was so high on drugs that he crashed his Corvette and ended up forgetting about Becky altogether. Anderson felt Becky's ordeal reflected real-life stories about porn actresses marrying ordinary civilians who later became jealous, angry, and violent over their new wives' pasts in porn. He cut the scene and decided to end Becky's story on an upbeat note: happily married, being wished well by her friends in the business, and ready to move with her new husband to a new life.
At the end of the movie Dirk is standing in front of a mirror. Suddenly he unzips his pants and exposes his rather large organ. It is a prosthetic device made from rubber. This prop was kept by Mark Wahlberg as a souvenir from the film. It was made from an easily biodegradable rubber and foam combination which, according to Wahlberg, has since already begun to deteriorate.
According to the DVD commentary, Paul Thomas Anderson intended for further scenes involving Rahad Jackson. After the bloody attempted robbery of his home, the police arrive, and Rahad gathers his weapons, ready to go out in a blaze of gunfire.
Originally, in the scene where Little Bill murders his wife and her lover, there were shots of the man and woman being struck by the bullets. It was eventually decided that this was too disturbing. Now, the camera shows Macy firing through the doorway, and then cuts to shots of the New Years Eve party crowd screaming in horror. Nina Hartley and the now unseen actor decided to actually have sex on the first take of the deleted shot, until producer JoAnne Sellar made it clear that this would not be acceptable.
At an early screening of the film, a group of teenage students attended the film. During the famous murder-suicide scene, when Little Bill grabbed the gun, the group started cheering. Paul Thomas Anderson was also at the screening and felt that he had screwed up the entire scene. They kept on cheering when Macy's character killed his wife and her lover, and then suddenly fell silent when Macy's character killed himself. Anderson didn't feel the same way anymore.
During Rollergirl's final scene, she cleans her room while wearing headphones. The song she listens to is "Voices Carry" by 'Til Tuesday. The lead singer, Aimee Mann, is married to Michael Penn, who performed original music for the film, and appears briefly as a music producer for Dirk and Reed.