April 10 — Claire Trevor, whose repertory of tough dames and femme fatales includes her Oscar-winning role as Edward G. Robinson’s mistress in Key Largo, died Saturday at age 91. The actress died in a hospital near her home in Newport Beach, Calif., friends said.

Trevor acted in some 70 films and 12 television productions, mostly from the 1930s through the 1950s, and was best known for supporting roles as women who stray from the path of virtue but end as heroines. She won a Best Supporting Actress Oscar in 1948 for her role in Key Largo as Gaye Dawn, the alcoholic mistress of cruel gangster Edward G. Robinson, who, in one famous scene, makes her sing for her next drink. The degraded Dawn saves hero Humphrey Bogart from the gangster’s clutches only to be jailed as an accessory.

In John Ford’s 1939 Western classic Stagecoach, perhaps her most famous role, Trevor played Dallas, an outcast saloon prostitute who finds love and a second chance with the outlaw Ringo Kid (John Wayne). Trevor received top billing in the film, which launched the career of the lesser-known Wayne. She was nominated for other Academy Awards in one of her three later pictures with Wayne — The High and the Mighty in 1954 — and also for her 1937 performance as Bogart’s girlfriend in a Manhattan, N.Y., slum in Dead End. Trevor’s women were often tougher than the men she fancied in noirs like Raw Deal, Born to Kill, and Murder My Sweet. Her femme fatale always lost out to the ingénues who were her romantic rivals, either through her own fatalistic schemes or through a last-minute pang of regret.

Born Claire Wemlinger in New York in 1909 (although some sources claim 1910 and 1912), she was raised in Larchmont, New York. After graduating from high school in Mamaroneck, she enrolled at Columbia University. She then left to study briefly at the American Academy of Dramatic Arts. The expressive blonde began her film career in the late 1920s and appeared on Broadway and in Vitaphone short films in 1932. The next year, her first films, Jimmy and Sally and Life in the Raw, began a career of mostly supporting roles. After her movie career tapered off in the 1950s, Trevor appeared on radio and television, winning an Emmy for Best Live Television Performance for her work in an adaptation of Sinclair Lewis’ novel Dodsworth. Her last film role was in Norman Rockwell’s Breaking Home Ties, made for television in 1987.

Trevor outlived her husband, Hollywood producer and agent Milton Bren. A drama enthusiast, she donated $500,000 last year to the University of California, Irvine, School of the Arts, which named the Claire Trevor Bren Theater Stage after her. She also traveled extensively and took up oil painting. In 1998, Trevor, along with all available past Oscar winners, appeared onstage at the 70th Annual Academy Awards in the “Oscar Family Album” segment.