James Byron Dean (February 8, 1931 – September 30, 1955) was an American actor. He became one of the most influential figures in Hollywood in the 1950s, despite a career that lasted only five years. His impact on cinema and popular culture was profound, even though he appeared in just three major films. Rebel Without a Cause (1955), in which he portrayed a disillusioned and rebellious teenager, East of Eden (1955), which showcased his intense emotional range, and Giant (1956), a sprawling drama, have been preserved in the United States National Film Registry by the Library of Congress for their "cultural, historical, or aesthetic significance". He was killed in a car accident at the age of 24 in 1955, leaving him a lasting symbol of rebellion, youthful defiance, and the restless spirit.

Dean was the first actor to receive a posthumous Academy Award nomination for Best Actor for his role in East of Eden. The following year, he earned a second nomination for his performance in Giant, making him the only actor to receive two posthumous acting nominations. In 1999, he was honored by the American Film Institute, being ranked as the 18th greatest male film star from Golden Age Hollywood on their "AFI's 100 Years...100 Stars" list. Time magazine recognized Dean as one of the "All-Time Most Influential Fashion Icons."

Dean's film roles and style had a strong impact on Hollywood, capturing the spirit of 1950s youth and creating an enduring legacy that shaped American pop culture and defined rebellious, countercultural attitudes for generations.

Dean was born on February 8, 1931, in Marion, Indiana, the only child of Mildred Marie Wilson and Winton Dean. He claimed that his mother was partly Native American and that his father belonged to a "line of original settlers that could be traced back to the Mayflower". Six years after his father had left farming to become a dental technician, Dean moved with his family to Santa Monica, California. He was enrolled at Brentwood Public School in the Brentwood neighborhood of Los Angeles but transferred soon afterward to the McKinley Elementary School. The family spent several years there, and by all accounts, Dean was very close to his mother. According to Michael DeAngelis, she was "the only person capable of understanding him". In 1938, Dean's mother was suddenly struck with acute stomach pain and quickly began to lose weight. She died of uterine cancer when Dean was nine years old. Unable to care for his son, Dean's father sent him to live with his aunt and uncle, Ortense and Marcus Winslow, on their farm in Fairmount, Indiana, where he was raised in their Quaker household. Dean's father served in World War II and later remarried.

In his adolescence, Dean sought the counsel and friendship of a local Methodist pastor, the Rev. James DeWeerd, who seems to have had a formative influence upon Dean, especially upon his future interests in bullfighting, car racing, and theater. According to Billy J. Harbin, Dean had "an intimate relationship with his pastor, which began in his senior year of high school and endured for many years". An alleged sexual relationship was suggested in Paul Alexander's 1994 book Boulevard of Broken Dreams: The Life, Times, and Legend of James Dean. In 2011, it was reported that Dean once confided in Elizabeth Taylor that he was sexually abused by a minister approximately two years after his mother's death. Other reports on Dean's life also suggest that he was sexually abused by DeWeerd either as a child or as a late teenager.

Dean's overall performance in school was exceptional, and he was a popular student. He played on the baseball and varsity basketball teams, studied drama, and competed in public speaking through the Indiana High School Forensic Association. After graduating from Fairmount High School in May 1949, he moved back to California to live with his father and stepmother, Ethel Case Dean. Dean enrolled in Santa Monica College and majored in pre-law. He transferred to University of California, Los Angeles (UCLA) for one semester and changed his major to drama. His attempt to reconcile with his father ended with an impasse of "uncommunicative antagonism" caused by Winton's efforts to direct him into a more traditional career. He pledged to the Sigma Nu fraternity but was never initiated. While at UCLA, Dean was picked from a group of 350 actors to portray Malcolm in Macbeth. At that time, he also began acting in James Whitmore's workshop. In January 1951, he dropped out of UCLA to pursue a full-time acting career. Of his pursuance of an acting career, Dean later said, "The decision to act was never prompted. My whole life has been spent in a dramatic display of expression."

In 1950, Dean made his television debut in a Pepsi commercial. He quit college to act full-time and was cast in his first speaking part, as John the Apostle in Hill Number One, an Easter television special dramatizing the Resurrection of Jesus. Dean worked at the widely filmed Iverson Movie Ranch in the Chatsworth area of Los Angeles during the production of the program, for which a replica of the tomb of Jesus was built on location at the ranch. Dean subsequently obtained three walk-on roles in movies: as a soldier in Fixed Bayonets! (1951), a boxing cornerman in Sailor Beware (1952), and a youth in Has Anybody Seen My Gal? (1952). While struggling to gain roles in Hollywood, Dean also worked as a parking lot attendant at CBS Studios. During that time, he met Rogers Brackett, a radio director for an advertising agency, who offered him professional help and guidance in his chosen career, as well as a place to stay. Brackett opened doors for Dean and helped him land his first starring role on Broadway in See the Jaguar.

In July 1951, Dean appeared on Alias Jane Doe, which was produced by Brackett. In October 1951, following the encouragement of actor James Whitmore and the advice of his mentor Rogers Brackett, Dean moved to New York City. There, he worked as a stunt tester for the game show Beat the Clock, but was subsequently fired for allegedly performing the tasks too quickly. He also appeared in episodes of several CBS television series, The Web, Studio One, and Lux Video Theatre, before gaining admission to the Actors Studio to study method acting under Lee Strasberg. In 1952, he had a nonspeaking bit part as a pressman in the movie Deadline – U.S.A., starring Humphrey Bogart.