Anyone could imitate Marlon Brando (search) — it was as simple as a scowl, a nasal voice and a scratch of the cheek — but few could copy the skill that made him an icon.

The two-time Oscar winner, who died at age 80, popularized the Method style of performing, which stripped away grandiose theatricality in favor of a deeper psychological approach to inhabiting a character.

Generations of young actors were electrified by Brando's work as conflicted characters in "A Streetcar Named Desire," "On the Waterfront" and "The Wild One," men who were emotionally vulnerable but savagely dangerous at the same time.

He was the bridge between the heroic screen purity of earlier stars such as Cary Grant, Gary Cooper and Henry Fonda and a generation of gritty, conflicted anti-heroes played by the likes of Robert De Niro, Jack Nicholson and Dustin Hoffman.

"He was like a godfather to many young actors worldwide but particularly in this country," said Robert Duvall, Brando's "Godfather" co-star.

Even directors who never worked with him benefited indirectly — actors were more willing to push themselves, delve deeper into their own psyches, and submit to endless retakes of scenes both to get it right and try things different ways.

"For my generation and for generations to come, he virtually defined truth and honesty, as an actor and then as a public persona," "Taxi Driver" director Martin Scorsese (search) said Friday. "Everything that we know about the power of great screen acting relates back to him: when you watch his work in 'On the Waterfront' or 'Last Tango in Paris,' you're watching the purest poetry imaginable, in dynamic motion."

Brando's impact started decades ago with James Dean, who adapted his fellow actor's streetwise demeanor in a career cut tragically short. To later generations, Brando embodied a no-nonsense ruggedness: in his pre-fame youth, Russell Crowe (search) once recorded a rock song titled "I Want to Be Like Marlon Brando."

His contemporaries also were impressed. "Marlon Brando is the epitome of actors today, and all actors since the 1950s have been mimicking him," Tony Curtis said.

But merely learning the tricks of Method acting didn't guarantee a great performance.

What set Brando apart was the way that technique unleashed his inner conflict. The same qualities that made Brando a world-class actor also made him, by some accounts, a world-class pain.

The method seemed to harness his anger, warmth, insecurity, charm, cruelty and weakness — separating those traits from the eccentric streak that would define him later in life.

"He was tremendously respected as an actor. I think his personal conduct or his beliefs or attitudes affected people," said the actress Janet Leigh, who knew him socially. "Not in a good way."

His tricks in front of the camera varied. He was famous for rehearsing endlessly, for reshooting scenes again and again.

Other times, like on "The Godfather," he would tape sheets of paper imprinted with his lines to co-stars Al Pacino and Duvall, reading off their chests while they faced away from the camera. He claimed it added spontaneity to his readings.

Eva Marie Saint, his co-star in "On the Waterfront," said he could incorporate bits of real life into the script.

The famous scene in which he picks up her dropped glove and uses it to toy with her reluctant and shy character was originally written without the glove. She dropped it in a rehearsal, and Brando began to toy with it while they read lines, pulling it over her hand.

Director Elia Kazan liked the suggestiveness of that, and asked them to do the same thing when the camera was rolling.

"This was an accident, and another actor would have picked it up and restarted the scene," Saint said. "That was the genius of Marlon, always working."