His debut TV role as an epileptic in the TV medical drama "Medic" aired in early 1955 and led to the 18-year-old Hopper being signed to a contract with Warner Bros., by whom he was cast in the role of Goon in "Rebel Without a Cause."
"The man was doing things I couldn't conceive of," Hopper said in an interview on "Inside the Actors Studio."
"He wasn't doing things that were on the written page. I mean, I could give a great line reading; I could do great gestures. I could preconceive everything, but he wasn't preconceiving anything. He was improvising. He was doing things that weren't on the page. He was using his imagination. He was expressing things with his body and through himself that were just way beyond my understanding."
The last time he saw Dean, who was killed in a car crash in 1955 at age 24, was at the end of working with him on "Giant," the Texas-set epic in which Hopper played Rock Hudson and Elizabeth Taylor's sensitive son as an adult.
"The most personal tragedy in my life was Dean," Hopper said in a 1987 Vanity Fair interview. "I was 19 years old and had such admiration for him."
Even after Dean's death, the young actor's advice stuck with Hopper.
"I was a very good technician," Hopper recalled in a 1990 interview with the Chicago Tribune, "but Dean was, like, so loose, creating all these wonderful things. So I grabbed him during the 'Chickie-run' scene, and threw him into a car, and I said, 'I thought I was the best, and now I see you, and I know you're better, and I don't even know what you're doing.' He said, 'Well, you have to do things, not show them. You have to take a drink from the glass, not act like you're drinking. Don't have any preconceived ideas. Approach something differently every time.' "
Hopper laughed. "That was the beginning of a lot of problems for me with directors."
On the set of the 1958 western "From Hell to Texas," Hopper refused to read his lines and gesture exactly the way the director, Hathaway, demanded in a scene. And, Hopper later recalled, Hathaway had him do take after take from 7 in the morning until about 10 at night before Hopper finally "cracked" and did it the director's way.
But the damage to Hopper's movie career was done: Warner Bros. dropped him and, he later said, that was the end of his career in Hollywood.
He moved to New York City, where he studied acting with Strasberg. He also became a professional photographer, shooting portraits for Vogue and other magazines. And he married Brooke Hayward, the daughter of actress Margaret Sullavan and producer Leland Hayward.
Hopper's Hollywood career was reinvigorated when his old nemesis, Hathaway, gave him a second chance by casting him in a small role in the 1965 John Wayne western "The Sons of Katie Elder" and later in the 1969 Wayne classic "True Grit."
Hopper also appeared in the low-budget, late-'60s drug movie "The Trip" and the biker film "The Glory Stompers," but he spent most of the decade making guest appearances on TV shows.
Throughout that period, Hopper told Playboy magazine in 1990, "I was looked on as a maniac and an idiot and a fool and a drunkard. And suddenly, I made 'Easy Rider,' man, and the whole world opens up to me."
Hopper's art will be the subject of an exhibition planned to open in July at the Museum of Contemporary Art in Los Angeles.
Hopper was married five times — to Hayward, with whom he had a daughter, Marin; Michelle Phillips; Daria Halprin, with whom he had a daughter, Ruthanna; Katherine LaNasa, with whom he had a son, Henry; and Victoria Duffy, with whom he had another daughter, Galen.
In January, Hopper filed for divorce from Duffy, whom he married in 1996. She reportedly stated in court filings that Hopper filed for divorce to cut her out of her inheritance, which Hopper denied.
Hopper's wife, children and one grandchild survive him, as does his brother, David, Hitz said.