Brando died in Los Angeles. The cause of death was not revealed, but he had suffered from congestive heart failure and was overweight.
The actor was perhaps the most influential of his generation, noted Bob Thomas of The Associated Press.
Brando shot to fame in 1947 with his groundbreaking performance in Tennessee Williams' play "A Streetcar Named Desire" as the brutal, animalistic Stanley Kowalski.
Brando, a devotee of the Method, gave a raw, vital performance under Elia Kazan's direction that had critics swooning. Using the technique, fostered by Russian director Konstantin Stanislavsky and popularized at Lee Strasberg's Actors Studio, actors such as Brando drew on their own psychology and experience in creating roles.
"There had never been such a display of dangerous, brutal male beauty on an American stage, its influence can still be felt, in fashion photography and sport as well as acting," wrote David Thomson in his New Biographical Dictionary of Film.
The actor was as famous for his off-screen antics as his on-screen performances. He could be intensely private, and yet he earned reams of publicity for his eccentric behavior and sometimes outlandish salary demands.
On "The Score" (2001), he refused to be on the set at the same time as director Frank Oz; he received $4 million for 10 minutes of acting in "Superman" (1978); he sent a woman who called herself Sacheen Littlefeather to decline his Oscar for "The Godfather" (1972).
But Brando was always held in esteem, often sought after even for a small part for the opening of "Scary Movie 2," which he turned down for health reasons.