Lou Rawls was born Louis Allen Rawls in Chicago on December 1, 1933, and was raised by his grandmother in the Ida B. Wells housing project on the city's South Side. He began singing at seven in the choir of Greater Mount Olive Baptist Church, and the local gospel circuit put him in touch with Sam Cooke, who was nearly three years older, and Curtis Mayfield. After Dunbar Vocational High School he sang briefly with Cooke in the Teenage Kings of Harmony and then with the Holy Wonders. In 1951 he took Cooke's place in the Highway QC's when Cooke left for the Soul Stirrers in Los Angeles, and the Chosen Gospel Singers soon brought Rawls to Los Angeles as well, where he joined the Pilgrim Travelers.

He enlisted in the United States Army in 1955 as a paratrooper with the 82nd Airborne Division, made 26 jumps and left three years later as a sergeant, then rejoined the Travelers. In 1958, touring the South with the group and Cooke, he was in a car crash. He was pronounced dead before reaching the hospital, lay in a coma for five and a half days and needed a year to recover, with his memory taking several months to return. He considered it a life-changing event. He sang at the Hollywood Bowl in 1959 with Dick Clark as master of ceremonies, and his first singles, "Love, Love, Love" and "Walkin' (For Miles)," came out on Shar-Dee, a label owned by Herb Alpert. In July 1961 the producer Nick Venet heard him at the Pandora's Box nightclub in Los Angeles and signed him to Capitol Records. In 1962 he sang backing vocals on two Cooke songs, "Bring It On Home to Me" and "That's Where It's At."

His Capitol years began with the jazz and blues records. Stormy Monday (1962) was an album of blues and jazz standards chosen by Rawls and cut in early 1962 with the Les McCann Trio, meaning McCann on piano, Leroy Vinnegar on bass and Ron Jefferson on drums, with Venet producing. Its ten songs ran from T-Bone Walker's title tune through Billie Holiday's "God Bless the Child," "Willow Weep for Me" and "'Tain't Nobody's Biz-Ness If I Do." Two big-band albums followed, Black and Blue (1963) and Tobacco Road (1964), with the pianist and arranger Onzy Matthews as musical director of a 17-piece band. Matthews was a Los Angeles jazz bandleader whose first big band had been started with help from Dexter Gordon and Curtis Amy, and both albums reached the Billboard charts. A three-song session Rawls cut with the Curtis Amy Sextet on March 11, 1963 stayed in the vault until a 2006 compilation. In 1965 Benny Carter arranged and conducted two more Capitol albums, Nobody But Lou and Lou Rawls and Strings, both produced by David Axelrod.

Live!, released in April 1966, was recorded at Capitol's Los Angeles studios before a small audience, with Axelrod producing and a quartet of Tommy Strode on piano, Herb Ellis on guitar, Jimmy Bond on bass and Earl Palmer on drums. Rawls's spoken introductions carry much of its character, including a "Southside Blues" monologue that leads into "Tobacco Road," and the program runs from "Stormy Monday" and "St. James Infirmary" to "The Shadow of Your Smile" and "The Girl from Ipanema." It was certified gold. The hit records that made his name, though, came from a soul album. Soulin' (1966) contained "Love Is a Hurtin' Thing," his first No. 1 on the R&B chart and a No. 13 pop single, and "Dead End Street" (No. 3 R&B, No. 29 pop) won him the Grammy for Best Male R&B Vocal Performance at the 1968 ceremony. He played the first evening of the Monterey International Pop Festival in 1967. Jazz stayed in the picture: on September 23, 1968, in Hollywood, he was one of two guest vocalists, alongside Nancy Wilson, on the Cannonball Adderley Quintet's In Person, singing "I'd Rather Drink Muddy Water" in front of Adderley, Nat Adderley, Joe Zawinul, Victor Gaskin and Roy McCurdy, a song he had also recorded on Stormy Monday.

Capitol dropped him in 1970. Bobby Hebb and Sandy Baron, who had written "A Natural Man," pressed the song on him and helped him win a contract with MGM; it reached No. 17 on the pop chart in 1971 and earned him a second Grammy at the 1972 ceremony. After a 1974 Bell album, She's Gone, he signed with Philadelphia International in 1976 under his new manager Martin Pichinson. All Things in Time sold a million copies, and its Kenny Gamble and Leon Huff song "You'll Never Find Another Love Like Mine" became his biggest hit, topping the R&B and adult contemporary charts, reaching No. 2 on the Hot 100 and selling a million as a single. "Lady Love" followed from When You Hear Lou, You've Heard It All (1977), and Unmistakably Lou brought a third Grammy for Best Male R&B Vocal Performance in 1978.

In 1980 he started the Lou Rawls Parade of Stars telethon for the United Negro College Fund, an annual event that had raised more than $250 million for the fund by the time he passed away. He took roles in television and film, among them Leaving Las Vegas (1995) and Blues Brothers 2000 (1998), where he was one of the Louisiana Gator Boys, voiced characters in cartoons including Hey Arnold!, sang the title character in a series of Garfield television specials, and received a star on the Hollywood Walk of Fame in 1982.

In 1988 he sang lead on "Save the Bones for Henry Jones," a track on Ray Charles's Columbia album Just Between Us, with Milt Jackson on vibraphone. Blue Note brought him back to jazz and blues in 1989. At Last, produced by Michael Cuscuna and Billy Vera and recorded at Sunset Productions in New York in early 1989 as part of the label's fiftieth-anniversary year, found Rawls singing live in the studio with a rhythm section of Richard Tee, guitarists Cornell Dupree and Steve Khan, bassist Tinker Barfield and drummer Chris Parker. The guests were Ray Charles on "That's Where It's At," the Cooke song Rawls had sung on in 1962, and Dianne Reeves on "Fine Brown Frame" and the title song, with Bobby Hutcherson on vibraphone, Stanley Turrentine and David Newman on tenor saxophone, and George Benson on guitar and background vocals for "You Can't Go Home." It reached No. 1 on Billboard's Contemporary Jazz Albums chart, was nominated for the Grammy for Best Jazz Vocal Performance, Male, and sent him to several European jazz festivals. It's Supposed to Be Fun (1990) followed on Blue Note, again with Cuscuna and Vera producing, and featured the altoist Hank Crawford and the tenor saxophonist Eddie Harris as soloists. Portrait of the Blues (Manhattan, 1993) kept the same producers and Crawford. In 2003 he made Rawls Sings Sinatra for Savoy Jazz, produced by Vera with arrangements by Benny Golson and Mike Melvoin.

In December 2005 it was announced that Rawls was being treated for lung cancer that had spread to his brain. He passed away on January 6, 2006, at Cedars-Sinai Medical Center in Los Angeles. His last public appearances had included his telethon in September 2005 and the national anthem before the second game of the 2005 World Series in Chicago, the city where he was born. In 2021 he was inducted posthumously into the Rhythm & Blues Hall of Fame.

Rawls was a baritone whose sound combined the weight of gospel, the plain speech of the blues and an easy, conversational delivery, and the spoken introductions he built into his sets became part of the act as much as the singing. His gospel apprenticeship, shared with Sam Cooke, ran through the Highway QC's and the Pilgrim Travelers, and his Capitol catalog set him beside the jazz players and arrangers Les McCann, Onzy Matthews, Benny Carter and Benny Golson.

The jazz side of his work is real, and it is a minority of it. It runs through the Capitol records of 1962 to 1966, his guest turn with Cannonball Adderley, the Blue Note albums beginning in 1989 and the Sinatra set of 2003. The larger share of his career, and all three of his Grammy wins, belong to soul and rhythm and blues: the Capitol soul singles, the MGM comeback and the Philadelphia International hits written by Gamble and Huff, plus decades of television, advertising and charity work. Reviewers have long noted that the commercial years overshadowed the early jazz and blues records. The subgenre tags above mark the jazz and blues side of his catalog, not the whole of his career.