Odetta died Tuesday of heart disease at Lenox Hill Hospital, said her manager of 12 years, Doug Yeager. She was admitted to the hospital with kidney failure about three weeks ago, he said.
In spite of failing health that caused her to use a wheelchair, Odetta performed 60 concerts in the last two years, singing for 90 minutes at a time. Her singing ability never diminished, Yeager said.
"The power would just come out of her like people wouldn't believe," he said.
With her booming, classically trained voice and spare guitar, Odetta gave life to the songs by workingmen and slaves, farmers and miners, housewives and washerwomen, blacks and whites.
First coming to prominence in the 1950s, she influenced Harry Belafonte, Bob Dylan, Joan Baez and other singers who had roots in the folk music boom.
An Odetta record on the turntable, listeners could close their eyes and imagine themselves hearing the sounds of spirituals and blues as they rang out from a weathered back porch or around a long-vanished campfire a century before.
"What distinguished her from the start was the meticulous care with which she tried to re-create the feeling of her folk songs; to understand the emotions of a convict in a convict ditty, she once tried breaking up rocks with a sledge hammer," Time magazine wrote in 1960.
"She is a keening Irishwoman in `Foggy Dew,' a chain-gang convict in `Take This Hammer,' a deserted lover in `Lass from the Low Country,"' Time wrote.
Odetta called on her fellow blacks to "take pride in the history of the American Negro" and was active in the civil rights movement. When she sang at the March on Washington in August 1963, "Odetta's great, full-throated voice carried almost to Capitol Hill," The New York Times wrote.
She was nominated for a 1963 Grammy awards for best folk recording for "Odetta Sings Folk Songs." Two more Grammy nominations came in recent years, for her 1999 "Blues Everywhere I Go" and her 2005 album "Gonna Let It Shine."
In 1999, she was honored with a National Medal of the Arts. Then-President Bill Clinton said her career showed "us all that songs have the power to change the heart and change the world."
"I'm not a real folksinger," she told The Washington Post in 1983. "I don't mind people calling me that, but I'm a musical historian. I'm a city kid who has admired an area and who got into it. I've been fortunate. With folk music, I can do my teaching and preaching, my propagandizing."
Among her notable early works were her 1956 album "Odetta Sings Ballads and Blues," which included such songs as "Muleskinner Blues" and "Jack O' Diamonds"; and her 1957 "At the Gate of Horn," which featured the popular spiritual "He's Got the Whole World in His Hands."
Her 1965 album "Odetta Sings Dylan" included such standards as "Don't Think Twice, It's All Right," "Masters of War" and "The Times They Are A-Changin'."
In a 1978 Playboy interview, Dylan said, "the first thing that turned me on to folk singing was Odetta." He said he found "just something vital and personal" when he heard an early album of hers in a record store as a teenager. "Right then and there, I went out and traded my electric guitar and amplifier for an acoustical guitar," he said.
Belafonte also cited her as a key influence on his hugely successful recording career, and she was a guest singer on his 1960 album, "Belafonte Returns to Carnegie Hall."
She continued to record in recent years; her 2001 album "Looking for a Home (Thanks to Leadbelly)" paid tribute to the great blues singer to whom she was sometimes compared.
Odetta's last big concert was on Oct. 4 at San Francisco's Golden Gate Park, where she performed in front of tens of thousands at the Hardly Strictly Bluegrass festival, Yeager said. She also performed Oct. 25-26 in Toronto.
Odetta hoped to sing at the inauguration of President-elect Barack Obama, though she had not been officially invited, Yeager said.
Born Odetta Holmes in Birmingham, Ala., in 1930, she moved with her family to Los Angeles at age 6. Her father had died when she was young and she took her stepfather's last name, Felious. Hearing her in glee club, a junior high teacher made sure she got music lessons, but Odetta became interested in folk music in her late teens and turned away from classical studies.
She got much of her early experience at the Turnabout Theatre in Los Angeles, where she sang and played occasional stage roles in the early 1950s.
"What power of characterization and projection of mood are hers, even though plainly clad and sitting or standing in half light!" a Los Angeles Times critic wrote in 1955.
Over the years, she picked up occasional acting roles in TV and film. None other than famed Hollywood columnist Hedda Hopper reported in 1961 that she "comes through beautifully" in the film "Sanctuary."
In the Washington Post interview, Odetta theorized that humans developed music and dance because of fear, "fear of God, fear that the sun would not come back, many things. I think it developed as a way of worship or to appease something. ... The world hasn't improved, and so there's always something to sing about."
Odetta is survived by a daughter, Michelle Esrick of New York City, and a son, Boots Jaffre, of Fort Collins, Colo. She was divorced about 40 years ago and never remarried, her manager said.
A memorial service was planned for next month, Yeager said.