Mercedes McCambridge, the intense, dark-eyed character actress who was regarded as one of the best of her generation by many of her colleagues—including Orson Welles, who once called her "the world's greatest living radio actress"—died in San Diego on March 2, 2004, of natural causes, AP reported. Ms. McCambridge range of roles was a testament to what others recognized as a confident and brash persona. She followed Uta Hagen in the part of the man-eating Martha in the Broadway production of Edward Albee's Who's Afraid of Virginia Woolf?, and took over for Irene Worth as a domineering grandmother in Neil Simon's Lost in Yonkers. When young Linda Blair spoke, as the possessed child in the 1973 horror film "The Exorcist," it was Ms. McCambridge's terrifying rasp audiences heard.

But she was best known for her role as a ruthless secretary and lover of Broderick Crawford Huey P. Long-like politician in 1949's "All the King's Men." It was her first film role and she won an Oscar for her work. Hollywood would use her infrequently, however, uncertain how to cast her outsized personality and hard-edged looks. She played a rough-riding, jealous relation of Rock Hudson's cattle baron in George Steven's "Giant," and gave as good as she got opposite Joan Crawford in the famously over-the-top 1954 Nicholas Ray western "Johnny Guitar." She and Crawford, another strong woman, famously loathed each other on first sight, and their rivalry charged their scenes on screen. (The movie, converted into a musical, is currently playing Off-Broadway.) Always, she was best at playing characters who lived at a high emotional pitch.

Her radio colleague, Orson Welles, worked with her only once on film, in 1958's lurid film noir, "Touch of Evil," in which she played the androgenous leader of a youth gang.

Born Carlotta Mercedes Agnes McCambridge in Joliet, Illinois, on March 17, 1918, and educated at Mundelein College, she first made her name in radio, appearing in hundreds of programs. According to the Internet Movie Database, her distinctive, muscular voice was heard on "Sanctum Mysteries," "Big Sister," "The Ford Theater," "Studio One," "Murder At Midnight," "One Man's Family," "I Love A Mystery" (in which she supplied all the female voices), "The Guiding Light" and others.

After appearing in three successive Broadway flops in the late '40s—A Place of Our Own, Woman Bites Dog and The Young and Fair—she went to Hollywood, where she quickly landed the role in "All the King's Men."

Other theatre credits include Cages in 1963 in New York and Regina in The Little Foxes that same year in summer stock.

Her first husband, from 1941 to 1946, was William Fifield. They had one child. She had another child with Fletcher Markle, whom she married in 1950. They divorced in 1962. Her autobiography, "A Quality of Mercy," was published in 1981. In it, she recounted her battles with alcoholism. She also wrote "The Two of Us" (1961), an account of a world-wide tour she took with her son, John Markle (he was Fifield's son, but later took the name of his mother's second husband). That son's life ended in tragedy; in 1987 he shot his wife and two daughters and then killed himself.