In the scene where Adam refuses to accept Cal's money, the script called for Cal to turn away in anger from his father. It was James Dean's instinct to embrace him instead. This came as a surprise to Raymond Massey, who could think of nothing to do but say, "Cal! Cal!" in response.
Elia Kazan, in his autobiography "A Life" (1988), said that Raymond Massey came to despise James Dean. Kazan did nothing to dispel the tension between the two, as it was so right for their characters in the film.
Elia Kazan first toyed with the idea of casting Marlon Brando as Cal and Montgomery Clift as Aaron, but at 30 and 34 years old, respectively, they were simply too old to play John Steinbeck's teenage brothers. Ironically, the youthful-looking Paul Newman, who was one year Brando's junior, was a finalist for the part of Cal, which eventually was played by Newman's friend James Dean. Dean was seven years younger than Newman.
During the production of the film, Elia Kazan used to write letters to his friend John Steinbeck, with whom he had worked closely on the original screenplay for Viva Zapata! (1952), to keep him abreast of the film's progress. Steinbeck thought James Dean was a perfect Cal, and tremendously enjoyed the final film.
Timothy Carey, who had a small part as Joe the bouncer, drove director Elia Kazan to such distraction with his bizarre behavior that Kazan, a longtime avowed pacifist, physically attacked him, the only time he had ever done such a thing.
James Dean and Paul Newman were filmed together in a crude screen test in New York that still exists, according to Dean biographer David Dalton in "The Mutant King" (1974). In the screen test, Newman is quite cool and stares straight ahead while Dean is more animated, and is flipping something up and down in and out of his hand like George Raft and his nickel in Scarface (1932). When Dean is asked what the object is, he admits that it is a switchblade, the premier symbol of the juvenile delinquent menace much feared in the 1950s. In an excerpt of the test now available on the Internet, there is no evidence of Dean playing with a knife.
The film's premiere, at New York's Astor Theater, also served as the first in a long line of benefit events organized to help pay for the purchase and renovation of the newly acquired home of The Actors Studio, which had itself provided arguably the film's three most powerful performances, courtesy of James Dean, Julie Harris, and Jo Van Fleet, as well as strong supporting turns from Lois Smith, Barbara Baxley, and Lonny Chapman (and to whom Warner Brothers prez Jack L. Warner had generously offered the entire proceeds of the New York premiere). The celebrity ushers on hand included Margaret Truman, 'Arlene Francis (I)', Jayne Meadows, Marjorie Steele (aka Mrs. Huntington Hartford), Roberta Peters, Carol Channing, Eva Marie Saint, and... oh yeah, Marilyn Monroe. Moreover, the event's organizer, Morton Gottlieb, worried that patrons would balk at the hefty fee charged for just a movie, organized a lavish post-screening party featuring free entertainment, including Channing, accompanied by 'Jule Styne', singing "Diamonds Are a Girl's Best Friend" (Gottlieb having failed in his attempt to persuade Miss Monroe to reprise her hit from 1953's Gentlemen Prefer Blondes (1953)), composer 'Harold Arlen (I)' performing a piano medley, a song composed for the occasion, performed by its authors, Howard Dietz and Arthur Schwartz, and, last but hardly least, a young and still little known Sammy Davis Jr. (less than four months after the near-fatal auto accident which had cost him his left eye, and more than one year before he'd make his official Broadway debut in "Mr. Wonderful"), here making his Big Apple downtown debut and bringing down the house in the process.
In the book and movie, in 1917 Adam Trask unsuccessfully "invents" the refrigerated railroad car to ship produce. In reality, tens of thousands of such cars were in constant use by 1890; see Wikipedia "Refrigerator car" entry.
According to Elia Kazan in the first issue special DVD collector's edition, in an interview. Hr stated that, James Dean gave him a ride on his motorcycle after the first meeting. He realized that he thought Dean might not be a good actor but he was definitely Cal Trask.