Marlon Brando, whose blend of sensitivity and savagery brought him acclaim as one of the greatest actors of his generation and whose tumultuous personal life made him an icon of defiance onscreen and off, died Thursday. He was 80.

He died at a Los Angeles hospital, whose spokeswoman said he had lung failure. He also suffered from heart ailments.

Moody performers such as Humphrey Bogart made the stiff, brilliantined leading man seem obsolete by the 1940s. But it was Brando -- sweaty, swaggering, mumbling, wounded, brutish and beautiful -- who further heightened expectations in postwar cinema. He won two Academy Awards, for "On the Waterfront" and "The Godfather," and created a menagerie of unforgettable characters in films from "A Streetcar Named Desire" to "Apocalypse Now."

His naked emotional display on the screen was matched by an often-tragic series of events in his private life, from his pain-racked childhood to his failed marriages to his self-castigating courtroom pleas during his son Christian's manslaughter trial. He also made disastrously indulgent career choices as he came to view acting as a lark and spent decades teetering between being a has-been and creating major milestones in performance.

His artistry in his greatest films transcended everything. As Newsweek cultural observer Jack Kroll wrote in 1994, "That will be Brando's legacy whether he likes it or not -- the stunning actor who embodied a poetry of anxiety that touched the deepest dynamics of his time and place."

It was clear from Brando's screen debut as a scornful paraplegic war veteran in "The Men" (1950) and his explosive work as Stanley Kowalski in "A Streetcar Named Desire" (1951) that he was a towering new breed of actor, able to display a naked and raw soul that ached with passion but also was unpredictably bestial.

One critic noted that in "The Men," Brando "comes like a blood transfusion into cinema acting," and later writers confirmed his legacy: With his pinup magnetism and dazzling range, he simply dominated all discussions about film acting.

One of his greatest accomplishments as an actor was his ability to penetrate the deepest thoughts of his characters and convey their motivations finely and believably. He drew on a lifetime of emotional distress, his brilliance at mimicry and his own intuition to bring new dimensions of psychological motivation to his roles. Although his characters were capable of raping and threatening, he was praised for making those actions appear poetic and tragic, bestowing timeless resonance to his art.

Few other actors made so many instant classics. In more than 40 films, his gallery of most-admired performances includes: "Viva Zapata!" (1952), as Mexican revolutionary Emiliano Zapata; "Julius Caesar" (1953), as Marc Antony; "On the Waterfront" (1954), as longshoreman Terry Malloy, who takes a lonely stand against organized crime; "The Wild One" (1954), as a motorcycle gang leader; and "Sayonara" (1957), as a military officer who romances a Japanese dancer.

After a series of 1960s flops, he experienced an unexpected renaissance in the 1970s with "The Godfather" (1972), as mafia chieftain Vito Corleone; "Last Tango in Paris" (1972), as a man who, after his wife's suicide, goes on a sexual spree that is both liberating and tortuous; and "Apocalypse Now" (1979), as Army Col. Walter E. Kurtz, a symbol of madness during the Vietnam War.

Although his role was brief, he also played Jor-El, the title superhero's father, in the blockbuster "Superman" (1978).

Of eight Oscar nominations, he won twice for best actor. He also won an Emmy Award for a supporting role as George Lincoln Rockwell, the American Nazi, in the television miniseries "Roots: The Next Generations" (1979).

Brando also had a huge impact on public behavior. He was, at first, a strikingly muscular and vital figure who defined 1950s leather-jacketed masculinity. He wore jeans to swank parties, insulted starmaking gossip columnists and flaunted his preference for dark-skinned women, then a social taboo -- anything to pique the Hollywood system that tried to control his public image.

He infuriated studio executives by going millions of dollars over budget on his only directorial effort, the revenge Western "One-Eyed Jacks" (1961), and was largely blamed for immense cost overruns on the South Seas island set of "Mutiny on the Bounty" (1962).

"Mutiny" director Lewis Milestone was one of many directors and studio officials he confounded with his distaste for authority. "Before he would take direction, he would ask why," Milestone said. "Then when the scene was being shot, he put earplugs in so that he couldn't hear my direction."

Brando saw his overall attitude differently. "I am myself," he once said, "and if I have to hit my head against a brick wall to remain myself, I will do it."

Starting in the 1960s, Brando became one of the first actor-activists to march for civil and Native American rights. He memorably refused to accept his Oscar for "The Godfather," protesting what he said was discrimination against Native Americans on film and in government policy.

Instead, he dispatched to the Academy Awards a woman who claimed to be a Native American named Sacheen Littlefeather and read an abridged version of Brando's 15-page indictment of policies toward the Indians. Later, she was revealed to be an actress named Maria Cruz, winner of the 1970 Miss American Vampire competition.

Brando also participated in "Free Huey" protests after Black Panther leader Huey P. Newton was tried in 1968 for allegedly killing an Oakland, Calif., police officer.

In later years, Brando came to be seen more as a tabloid curiosity with his seemingly boundless personal setbacks. Over time, he represented the disintegration of a sex symbol, as his muscular physique crumbled and he ballooned to more than 300 pounds; he often broke his diets by persuading McDonald's employees to pitch french fries and Big Macs over his fence. He was a hulking and teary presence at his son's 1990 trial in the shooting death of his half-sister's lover.

He called Christian's mother "as cruel and unhappy a person as I've ever met" and added about his own abilities as a parent, "I know I could have done better."

The public read about the bitterness of his three marriages; the many paternity suits; his daughter Cheyenne's 1995 suicide; and his odd public behavior, such as kissing television host Larry King on the mouth during an interview before Brando signed off with, "Darling, goodbye."

That 1994 King interview featured Brando doing free-association wordplay, singing off-key, expressing dislike for psychoanalysis and expounding on commercialism, exploitation and his life, about which he said he had no regrets. He teased and prodded King about sweating under the lights.

It all seemed to be a show. As his greatest acting coach, Stella Adler, encouraged him: Be anything but dull.

Marlon Brando Jr., the youngest of three children, was born in Omaha to the former Dorothy Pennebaker, a vivacious beauty and local actress, and Marlon Brando Sr., an insecticide salesman. His father, of French-Alsatian lineage, had changed his surname from Brandeaux.

When the family moved to Illinois -- to Evanston and then Libertyville -- Dorothy Brando accused her often-absent husband of sabotaging her theatrical career. She turned increasingly to drink, including one night when her son found her naked in a bar. Brando later used that memory to great effect in "Last Tango," an example of his penchant for blurring the personal with his art.

The move to Illinois also propelled young Brando's unruliness in the face of authority, such as pouring hydrosulfate into his high school's ventilation system to create a rotten-egg smell. Other friends noted his insatiable curiosity about nature, his self-taught skill on drums and his love of bodybuilding -- all of which helped define his restless physical charisma.

The elder Brando sent his son to Shattuck Military Academy in Minnesota, where he began acting at the behest of a drama coach who was taken with his flair for melodramatics. Brando was expelled shortly before graduation because of pranks and a poor academic record.

In 1943, he moved to New York to join his sisters, Frances and Jocelyn, who were involved in the arts scene. He was a ditch digger, a department store elevator operator and a factory night watchman. He also became a roommate and friend of actor Wally Cox, the bashful star of "Mr. Peepers" and the voice of cartoon superhero Underdog.

Brando enrolled at the New School for Social Research's dramatic workshop, where his classmates included Harry Belafonte, Shelley Winters and Rod Steiger.

One of his instructors was Adler, who came from a distinguished family of Yiddish actors. One day in class, she asked her students to imitate chickens in a henhouse who had just learned they were about to be hit with an atomic bomb. While others flailed about, Brando sat still and pretended to lay an egg.

She was delighted to see one student true to being a chicken. Her motto was, "Don't act. Behave." She became Brando's mentor, and he learned from her what is known as Method acting.

"What Stella taught her students was how to discover the nature of their own emotional mechanics and therefore those of others," Brando once wrote. "She taught me to be real and not to try to act out an emotion I didn't personally experience during a performance."

In 1944, Brando was hired to play the teenage son Nels in John van Druten's "I Remember Mama." The hit play brought him a swath of admirers, including director Elia Kazan, who later co-founded the Actors Studio, which Brando joined.

Kazan persuaded producer Irene Selznick to hire Brando for the Broadway role of Stanley Kowalski in Tennessee Williams's "A Streetcar Named Desire." Kazan was said to have helped Brando overcome his fear of not memorizing lines and also taught the young actor to use props to his advantage, a skill he put to use when gently stroking objects (a countertop, a glove, a cat) in later film roles.

"Streetcar" and Brando's performance in it were hailed as landmark theatrical events. Kowalski was a revelation -- one of the angriest, sexiest men ever imagined, who uses his animal appeal to manipulate the affections of his wife, Stella, and terrorize his romantically delusional sister-in-law, Blanche DuBois.

Brando once wrote that he was not so much drawing on his own urges to shape Kowalski as drawing from brutish people he knew. "I was the antithesis of Stanley Kowalski," he wrote. "I was sensitive by nature and he was coarse, a man with unerring animal instincts and intuitions."

During the two-year Broadway run, Brando and Jessica Tandy, who played Blanche, did not get along. Tandy, who was classically trained, reprimanded Brando publicly for mumbling onstage, leaving her without the verbal cues she needed. He retaliated with a series of pranks, once sending word to drunken sailors on leave that Tandy was available backstage for sexual favors.

The play was a breakthrough in establishing the Brando persona -- a raw and mysterious magnetism that was at once frightful and compelling. Though physically intimidating, he stood only about 5-foot-9 and had soft, soulful facial features such as full lips and long eyelashes.

Hollywood sought him, but he turned down all offers except Stanley Kramer's independent production of "The Men." The film, released at the start of the Korean War, was not a popular success, largely owing to its downbeat topic of disabled war veterans.

The filmed version of "Streetcar" launched Brando onscreen, but he was upset when he lost the Oscar to Bogart in "The African Queen." Film historians considered Bogart's win sentimental, and the loss burnished Brando's dismissive views of the film community.

Two more Oscar-nominated parts, in "Viva Zapata!" and "Julius Caesar," earned him further praise for his versatility. A British film reviewer noted: To grasp Brando's range, just imagine John Gielgud, Brando's classically trained "Julius Caesar" co-star, trying to play Stanley Kowalski.

Gielgud invited Brando to join him in stage work, but Brando said he had no desire to return to the theater. "It's been said I sold out," biographer Patricia Bosworth quoted Brando as saying. "Maybe that's true -- but I knew what I was doing. I've never had any respect for Hollywood. It stands for greed, avarice, phoniness, crassness -- but when you act in a movie, you act for three months and then you can do what you want for the rest of the year."

He won the Oscar for best actor in Kazan's "On the Waterfront," marking an early pinnacle of his career with his performance as a conscience-stricken former boxer. Brando delivered to his screen brother, Rod Steiger, the "I coulda been a contender" speech, considered one of the great film moments of all time.

He relied on star power to carry many of his next films. He played Napoleon Bonaparte in "Desiree" (1954), gambler Sky Masterson in the musical "Guys and Dolls" (1955), the Asian interpreter in "The Teahouse of the August Moon" (1956) and a sympathetic Nazi in "The Young Lions" (1958).

Tiring of such commercial fare, he began looking for offbeat projects. He was the wandering musician in "The Fugitive Kind" (1959), an adaptation of Williams's play "Orpheus Descending," and the antihero in "One-Eyed Jacks."

Stanley Kubrick was originally slated to direct "One-Eyed Jacks," but he grew increasingly frustrated with Brando's concept for the film and instead went off to direct "Spartacus." The Western's budget, originally $2 million, zoomed to $6 million as Brando took over directorial duties and emphasized improvisational acting techniques, even with the extras in the cast. The studio cut the five-hour-long film, angering Brando and triggering one of his eating binges.

After another fiasco with "Mutiny on the Bounty" (1962), he spent more time on his social activism and entered his longest commercial slump as an actor with a series of films casting a critical gaze on American society.

He was a diplomat in "The Ugly American" (1963); a sheriff in a town of southern vipers in "The Chase" (1966); a square politician in "A Countess From Hong Kong" (1967), directed by Charlie Chaplin; and a repressed gay Army officer in "Reflections in a Golden Eye" (1967).

Brando considered his most successful role, by the measure of both acting and social protest, his turn as a British emissary sent to investigate a slave revolt in Gillo Pontecorvo's "Burn!" (1969). Again, it failed with the public.

Dealing with film and marital woes, he became depressed and began another of his increasingly habitual eating binges. He retreated to Tahiti, which he had discovered as a peaceful retreat while filming "Mutiny." He bought an entire atoll in 1967 for $270,000.

Out of nowhere, author Mario Puzo sent Brando the "Godfather" script, hoping he would play Don Vito Corleone. Brando agreed, seeing the part as a statement about corporate greed. Onscreen, he emulated the pinched voice of organized crime figure Frank Costello during a 1950s Senate hearing led by Estes Kefauver (D-Tenn.) and ate a large dinner with underworld potentates to copy their mannerisms.

He also was inventive on camera, supplying many memorable ad-libs, such as the orange slice he places in his mouth to amuse his screen grandson.

"The Godfather" and his next film, "Last Tango in Paris," in which he has a fatal fling with a young Frenchwoman, prompted a massive rethinking of Brando's career. "Last Tango in Paris," which received an X rating, featured a highly improvisational Brando using many autobiographical details to flesh out his character.

In her New Yorker review, critic Pauline Kael wrote that director Bernardo Bertolucci and Brando "have altered the face of an art form" and called the film revolutionary.

Brando said he made many of his later films for the money -- he reportedly was paid $3.7 million for 12 days of work on "Superman." But he never seemed anything short of mesmerizing, whether as a cross-dressing hired gun in the Western "The Missouri Breaks" (1976) or as a mischievous Mafia don in "The Freshman" (1990), spoofing his role in "The Godfather."

Critic Hal Hinson, writing about "The Freshman" in The Washington Post, said, "Brando is never less than a miraculously magnetic camera subject; just to have him in front of the lens is, in most cases, enough."

He earned his final Oscar nomination, for best supporting actor, as a lawyer in apartheid South Africa in "A Dry White Season" (1989).

Morbidly obese and depressed after the deaths of family members and friends, he spent the last decade more as an object of media curiosity than as an actor looking for his next challenge. He largely resigned himself to insubstantial parts in panned films such as "The Island of Dr. Moreau" (1996).

Ever the mischievous performer, he was said to spend his spare time as a ham-radio operator. He used vocal mimicry to talk to the outside world, but always in disguise.

His marriages to actresses Anna Kashfi, Movita Castenada and Tarita Teriipaia ended in divorce. He also had a long relationship with his former housekeeper, Christina Ruiz.

Survivors include a son from his first marriage, two children from his second marriage, a son from his third marriage and several children with Ruiz.

Marlon Brando won -- and turned down -- an Oscar for his performance as "The Godfather," above. He also won an Oscar for "On the Waterfront." Marlon Brando, right, in the famous taxicab scene of "On the Waterfront," the 1954 classic for which he won his first Oscar. Rod Steiger played his brother. Brando as Stanley Kowalski in Tennessee Williams's "A Streetcar Named Desire," a role Brando created on Broadway and re-created in Hollywood.Brando with Maria Schneider in "Last Tango in Paris," released in 1972 during a short-lived rebirth of his career.