Margaret O'Brien tested for the role of Judy but was rejected by Nicholas Ray after he described her answers to his probing questions as "too pat". Jayne Mansfield also tested but Ray declined to film her audition, considering her 'an hallucination' from the Warners casting department.
Debbie Reynolds was allegedly suggested for the part of Judy.
Jim Backus who played James Dean's father and was the voice of Mr. Magoo, taught Dean how to do the Mr. Magoo voice which Dean then used to deliver the line, "Drown them like puppies."
James Dean badly bruised his hand during the police station scene where he physically vents his rage on a precinct desk and had to wear an elastic bandage for a week.
James Dean did not get malaria during filming, as some have reported. Nick Adams had a relapse of an old case of malaria he got while he was a merchant marine.
James Dean originally wanted his friend Jack Simmons, whom he was living with at the time, for the part of Plato.
James Dean was free to star in the film because Elizabeth Taylor got pregnant, which delayed production of Giant.
James Dean's character's surname 'Stark' is an anagram of 'Trask' the surname of his character in East of Eden.
Marietta Canty's final film.
Natalie Wood was first considered too naive and wholesome for the role of Judy. She began changing her looks and eventually attracted the notice of director Nicholas Ray, who began an affair with her but still would not guarantee her the part, though he eventually relented. Both Ray and Wood later claimed that he changed his mind after she was in a car accident with Dennis Hopper and someone in the hospital called her a "goddamn juvenile delinquent".
Sal Mineo once said that on the day his death scene was shot, James Dean never let Sal out of his sight during the entire day.
Frank Mazzola, who plays "Crunch" in the film, was an actual street gang member when he was a student at Hollywood High School. He was a member of a gang called "The Athenians." As such, he served as a technical advisor to Director Nicholas Ray and coached other actors in regard to street gang attitudes and mannerisms.
2007: The movie's line "You're tearing me apart" was voted as the #97 of "The 100 Greatest Movie Lines" by Premiere magazine.
All three lead actors, James Dean, Sal Mineo, and Natalie Wood, died young under tragic circumstances: Dean died in a car accident, Mineo was stabbed, and Wood drowned. In addition, Edward Platt committed suicide in 1974.
Although playing a teenager, James Dean was actually 24 when the movie was filmed.
An alternative ending was shot in which Plato falls from the tower of the planetarium.
Director Nicholas Ray researched L.A. gangs by riding around with them for several nights.
For the knife fight between Jim (James Dean) and Buzz (Corey Allen), the actors used real switchblades and protected themselves by wearing chainmail under their vests.
In 2010, a 'New York Times' article about Nicholas Ray's widow Susan said she had in her archives an original, unused treatment for "Rebel" in which the ending was very different: Plato was going to shoot Jim and then blow himself up with a grenade. But another Times report in 2011, says the archive contains a Ray storyboard which shows it's Plato himself who is shot from the top of the planetarium. (A treatment is a preliminary synopsis of the story for a proposed movie that either gets written before the script is started as in this case or afterward so that executives at a potential producer's or investor's company won't have to read the whole script.)
In his article "Dangerous Talents," published in Vanity Fair Magazine in March 2005, Sam Kashner writes that director Nicholas Ray, screenwriter Stewart Stern, costar James Dean, and Sal Mineo himself all intended for Mineo's character Plato to be subtly but definitely understood as gay. Kashner says that although the Production Code was still very much in force and forbade any mention of homosexuality, Ray, Dean, Mineo, and Stern all worked together to insert restrained references to Plato's homosexuality and attraction to Jim, including the pinup photo of Alan Ladd on Plato's locker door, Plato's adoring looks at Jim, his loaded talk with Jim in the old mansion, and even the name "Plato," which is a reference to the Classical Greek philosopher. For that mansion scene, Dean suggested to Mineo that Plato should "look at me the way I look at Natalie."