Karl Malden, , an Academy Award-winning actor who excelled in plainspoken, working-class roles, including the awkward Mitch in "A Streetcar Named Desire" and a brave priest in "On the Waterfront," died Wednesday at his home in Los Angeles. No cause of death was immediately disclosed. He was 97.

Malden's bulbous nose and thinning hair made him one of the most familiar sights in movies and on television for five decades. In the 1970s, he became known to millions of viewers as a police veteran who partners with a young inspector played by Michael Douglas on the ABC drama series "The Streets of San Francisco."

The show led to Malden's 21-year role as the trench coat-wearing pitchman for American Express who urged customers not to leave home without their traveler's checks. He joked that this became his best-known part, despite his reputation as one of the most versatile actors in more than 70 films and television movies.

Malden was a steelworker before winning important stage roles on Broadway. He made his greatest mark on Hollywood in the early 1950s as part of a group of New York theater stars -- headed by actor Marlon Brando and director Elia Kazan -- who were trying to bring an unpredictable, realistic style of acting to audiences

"I hadn't met anyone that non-actorish before, non-theater-like," Kazan once said of Malden. "The minute I saw him, I knew he came from something. It turned out to be the steel mills, and it was a thing that was very important for a director, because you feel, `Here's a person who can play difficult parts, rough parts, physical parts, who doesn't get frightened easily, who's all there when I need him.' "

Kazan said Malden was a great player to have opposite Brando because he had the impression Malden could tell Brando to "go to hell" without being intimidated.

Kazan directed Malden and Brando in Tennessee Williams's drama "A Streetcar Named Desire" on Broadway in 1947 and then in the 1951 film version. Malden won the Oscar for his supporting role as Mitch, who romances an emotionally fragile Southern belle related to Brando's character, Stanley Kowalski. Jessica Tandy played the woman onstage and Vivien Leigh was in the film version.

Again working under Kazan, Malden was nominated for an Oscar in his role as the dockside priest who rallies a punched-out prizefighter (Brando) to stand against a corrupt union in "On the Waterfront" (1954). Malden brought actress Eva Marie Saint, whom he had known at an acting workshop in New York, to Kazan's attention for what would be her movie debut and Oscar-winning role as Brando's love interest.