Granger died Sunday of natural causes, said Ellen Borakove, a spokeswoman for the New York City medical examiner's office.
Granger, who died at his Manhattan home, was an overnight Hollywood success story. He was a 16-year-old student at North Hollywood High School when he got the notion that he wanted to act and joined a little theater group.
Talent scouts for movie mogul Samuel Goldwyn saw the handsome youngster and signed him to a contract. His first movie was "The North Star" in 1943, a World War II story that starred Anne Baxter and Dana Andrews.
"It was one of those miracle careers," he said. "I had no talent and no training whatsoever and suddenly I was thrown . . . (in) with Walter Huston, Erich von Stroheim, Anne Baxter, Ann Harding and Walter Brennan."
A decade later, at the height of his Hollywood stardom, he walked away from it to really learn his craft. He spent the rest of his career in a mix of movies, television and stage work.
Granger was born on July 1, 1925, in San Jose, Calif., where his father was a car dealer. The business went bust during the Depression and in 1933 the family moved to Los Angeles where he was subsequently spotted.
His career halted for U.S. Navy service during World War II -- "I was chronically seasick." But when he was mustered out he returned to Hollywood and the Goldwyn publicity machine.
"Goldwyn firmly believed in big hype and hoopla for his stars, so he'd publicize me in projects that were never even written just to get space in the fan magazines," Granger once recalled.
The magazines ran pictures of Granger in swim trunks cavorting with such stars as Debbie Reynolds, Ann Blyth and Jane Powell. But he said the only serious romance he had with a woman was with Shelley Winters.
In the 2007 memoir "Include Me Out," written with his partner Robert Calhoun, Granger says he was bisexual.
His lifelong romance with Winters was "very much a love affair." "It evolved into a very complex relationship, and we were close until the day she died," he said in a 2007 interview with The Associated Press.
A briefer affair with Ava Gardner began when both quarreled with their dates at a Hollywood Christmas party. "We met at the bar and left together," he recalled in the interview. "It was a short but pretty intense and enormously fun affair."
He also writes about his same-sex celebrity affairs. For a time, he lived with Arthur Laurents, writer of the stage and movie versions of "West Side Story" and "Gypsy." In New York, Granger says he had a two-night fling with Leonard Bernstein.
He made his Broadway debut in 1960 in "First Impressions," a musical version of Jane Austen's "Pride and Prejudice."
He later did two years with Eva Le Gallienne's repertory troupe and a considerable stint as the lead in the long-running thriller "Deathtrap."
Granger continued to make films over the years, but he said he preferred the stage: "I feel I'm much more relaxed in front of an audience than a camera. I feel the response. The live audience really turns me on and I like it."