Alwin Lopez Jarreau didn't come up through music school. He earned a psychology degree from Ripon College in 1962 and a master's in vocational rehabilitation from the University of Iowa in 1964, and worked by day as a rehabilitation counselor in San Francisco while singing at night — first in a jazz trio led by pianist George Duke, then, from 1967, in a duo with guitarist Julio Martinez at Gatsby's, a Sausalito nightclub. Music wasn't his job yet. It became one by 1968, when he decided to pursue it full time and moved to Los Angeles.

His major-label debut, We Got By (1975, Reprise), was a collection of his own songs, and it set the pattern for the rest of the decade: Glow (1976) followed, then the live double album Look to the Rainbow (1977), whose title track won him his first Grammy, for Best Jazz Vocal Performance. All Fly Home (1978) won him a second Grammy in the same category the following year. He also became known outside strict jazz circles in this period for his writing and performing the theme song to the 1980s TV series Moonlighting, and for joining the all-star lineup on 1985's charity single "We Are the World," which won Record of the Year, Best Pop Performance by a Duo or Group, and Best Music Video at the Grammys.

His commercial breakthrough came in 1981 with Breakin' Away, built around the hit "We're in This Love Together," which spent two years on the Billboard 200 and won Jarreau the 1982 Grammy for Best Male Pop Vocal Performance — a jazz vocalist crossing fully into the pop category and winning. Two years later, Jarreau (1983) became his third consecutive No. 1 album on the Billboard Jazz chart, and its lead single, "Mornin'," reached No. 21 on the Pop chart, No. 2 on Adult Contemporary, and No. 1 on Jazz simultaneously — the kind of three-chart spread that is basically crossover jazz's whole argument compressed into one single.

In 2006 he made a full collaborative album, Givin' It Up, with guitarist George Benson. The thirteen-track record found each of them covering the other's signature hit — Benson taking on "Mornin'," Jarreau taking on "Breezin'" — trading places on their own biggest songs. It paid off at the Grammys: "Mornin'" won Best Pop Instrumental Performance, and "God Bless the Child" (with guest vocalist Jill Scott) won Best Traditional R&B Vocal Performance, on top of a nomination for Best R&B Performance by a Duo or Group with Vocal for "Breezin'." By the end of his career, Jarreau had won 10 Grammy Awards, and he remains the only vocalist in history to win competitive Grammys in three separate categories: jazz, pop, and R&B.

He didn't get much of a retirement. Jarreau announced he was stepping back from performing on February 10, 2017, after struggling with exhaustion and respiratory and cardiac issues in his final years; he died of respiratory failure two days later, on February 12, 2017, at age 76.

Jarreau's voice was his instrument in the most literal sense: he built a career-defining reputation for scat singing and vocal percussion, using his voice to imitate horns, basslines, and drum patterns in a way that earned him the nickname "the Acrobat of Scat." That vocabulary put him in a lineage with jazz vocal improvisers going back to Louis Armstrong and Ella Fitzgerald, but he applied it inside pop and R&B song structures as comfortably as inside jazz standards — which is exactly what let him move between the three Grammy categories (jazz, pop, R&B) that no other vocalist has won competitively. His early years alongside pianist George Duke's trio in San Francisco gave him a jazz-combo foundation before he ever had a record contract, and that combo-honed improvisational instinct never left his pop records, even at their most produced.