Etta James, 73, the powerful rhythm-and-blues singer whose more than five-decade career spawned such enduring hits as "At Last" and "Tell Mama," making her a profound influence on younger generations of female vocalists, died Friday.

Ms. James, who suffered complications from leukemia, according to her manager, had been beset with a variety of health problems. In 2009, she was diagnosed with dementia; the following year, she was hospitalized with a staph infection. In December, weeks after the release of The Dreamer, which was billed as her final studio album, Ms. James' doctor told the Riverside (Calif.) Press-Enterprise that the singer, who also had been diagnosed with hepatitis C, was terminally ill with chronic leukemia.

A genre-bridging singer equally commanding and comfortable singing the blues, jazz, and rock-and-roll, Ms. James was a Grammy Lifetime Achievement Award-winner and a member of the Rock and Roll and Blues Halls of Fame. The legendary producer Jerry Wexler called her "the greatest of modern blues singers . . . the undisputed Earth Mother."

Born Jamesetta Hawkins in 1938 in Los Angeles, Etta James was the daughter of a 14-year-old mother and a father she never knew. She would later claim to have reason to believe her father was the legendary pool player Rudolf "Minnesota Fats" Wanderone Jr.

Ms. James began singing in the gospel choir of a Los Angeles church at age 5. She knew even then that she would be a performer, she told the Las Vegas Review-Journal in 2006, "because I was always a show-off." At an early age, she developed a taste for what she referred to as "rotgut, lowdown blues," but her mother also made her listen to the smoother sounds of Frank Sinatra and Nat "King" Cole. Her music would reflect that combination of influences throughout her career.

As a teenager, her vocal group, the Creolettes, was discovered by the bandleader Johnny Otis, who rechristened them the Peaches, after Ms. James' nickname. (Otis, as it turned out, also died this week, at age 90 on Tuesday.)

In 1955, the group scored a No. 1 R&B hit with an answer song to Hank Ballard's risqué "Work With Me Annie" called "The Wallflower." (Its original title was "Roll With Me Henry," which was considered too sexually suggestive for the era.) The Peaches scored one more hit, with "Good Rockin' Daddy," before Ms. James went solo. By 1956, she was on tour, opening for Little Richard.

Ms. James' solo career failed to catch fire in the late '50s. Then she signed with the Chicago blues label Chess and, in 1960, released At Last!, an album that surrounded her husky voice with lush strings in an effort to court a broader pop audience than usual for a label that was home to the electric bluesmen Howlin' Wolf and Muddy Waters.

It worked. The album scored four pop hits, including the title cut, written by Mack Gordon and Henry Warden for the 1941 musical Orchestra Wives. It became Ms. James' signature song and a perennially popular first-dance choice at wedding receptions. In 2009, Beyoncé Knowles sang "At Last" at an inaugural ball while President Obama danced with his wife. Knowles had portrayed James in Cadillac Records, a 2008 movie that depicted a fictional affair between the singer and Chess cofounder Leonard Chess.

(Shortly thereafter, Ms. James told a Seattle concert audience, "I can't stand Beyoncé. She had no business up there on a big ol' president day, gonna be singing my song that I've been singing forever." She later apologized: "I didn't really mean anything. Even as a little child, I've always had that comedian kind of attitude.")

In the early 1960s, Ms. James began a decades-long struggle with heroin addiction. While she could never sustain the career momentum or achieve the broad popularity of such '60s soul standouts as Aretha Franklin or Otis Redding, she continued to record emotionally gripping music. One such career highlight was the 1968 album Tell Mama, recorded at FAME Studios in Muscle Shoals, Ala., which, besides the title cut, included the characteristically fierce "I'd Rather Go Blind."

By the 1970s, Ms. James was no longer scoring pop hits. Continuing to use heroin and, at times, stealing to support her habit, she was sent to rehab by court order in 1973. She recorded the underappreciated classic Deep in the Night with Wexler in 1978 and that year played a number of dates opening for the Rolling Stones.

After finally kicking her addiction with a stay at the Betty Ford Clinic in 1988, she made a comeback album, Seven Year Itch. And she won her first (of three) Grammy Awards for Mystery Lady, a 1994 tribute to Billie Holiday, whom Ms. James met in 1955, when she was 17. At the time, Holiday, then 40 and a junkie, warned her: "Don't let this happen to you."

In 2003, Ms. James published her autobiography, Rage to Survive: The Etta James Story, and she toured and recorded throughout the 2000s. She declined to participate in filmmaker Martin Scorsese's 2004 documentary series, The Blues, but the next year, after watching the series, she recorded the album Blues to the Bone.

"Etta James' voice is just as commanding as it was when she was young, but it's different - deeper, tougher," the director wrote in the liner notes. She's "laying out the full measure of life for those of us out there on the receiving end."

Late in life, Ms. James, who sang "At Last" on Dancing With the Stars in 2009, became a paragon of authenticity to a younger generation, a role model for female vocalists averse to lip-synching or Auto-Tuning in an overly processed digital age.

In 2006, Christina Aguilera called Ms. James "my all-time favorite singer. . . . All of Etta's old songs, countless songs I could name, I grew up listening to. That music was always such a huge escape for me." In 2009, the British pop star Adele called Ms. James her "favorite singer ever. I can sing any of her songs. They're all amazing."

Ms. James is survived by her husband of 42 years, Artis Mills, and sons Donto and Sametto James. Mills and Donto James have been involved in a court dispute over the administration of Ms. James' estate.

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