Les McCann, the pianist and vocalist who was an innovator of the funky, soulful, bluesy style known as soul jazz, has died. He was 88.

McCann died on Friday, Dec. 29, at a hospital in Los Angeles. His death was confirmed Monday by his manager Alan Abrahams. McCann had developed pneumonia a week earlier.

McCann recorded more than 50 albums as a leader during a career that spanned 64 years. He first came to prominence as a piano player in the 1960s, then began emphasizing his singing as well as incorporating more of the electric keyboard, clavinet, and synthesizer. With this, he was among the pioneers of the “soul jazz” style, which not only formed its own musical movement with an adoring audience but also went on to influence funk, R&B and hip-hop artists in the decades to come.

While McCann was a legend in the jazz world, he was most widely known to the general public for his performance and recording of the Gene McDaniels tune “Compared to What,” a protest song that criticized the Vietnam War. McCann’s version of the song, recorded with saxophonist Eddie Harris and trumpeter Benny Bailey at the 1969 Montreux Jazz Festival and released on the album Swiss Movement that same year, became a crossover hit that reached the Billboard pop charts.

McCann’s recordings have also been widely sampled by nearly 300 hip-hop artists, including A Tribe Called Quest, Cypress Hill, De La Soul, the Notorious B.I.G., Dr. Dre, Snoop Dogg, Nas, and Mary J. Blige.

McCann was born Sept. 23, 1935, in Lexington, Ky. He grew up in a musical family of four; his father was a fan of jazz and his mother liked opera, and most of the family would sing in church choirs. In his youth, McCann played the tuba and drums in his school’s marching band. He then went on to be a mostly self-taught pianist.

While serving in the U.S. Navy, McCann won a talent competition, which led to an appearance on The Ed Sullivan Show. After leaving the navy, he moved to California and formed his own jazz trio. He declined an offer to play in Cannonball Adderley’s band, instead wanting to devote himself to his own music.

Between 1960 and 2018, McCann released 54 albums as a leader with record labels including Atlantic, Impulse!, Pacific Jazz, Limelight, A&M and MusicMasters. As a sideman, he appeared on recordings with Richard “Groove” Holmes, Stanley Turrentine, Lou Rawls, Bill Evans, and others.

McCann had a stroke in the mid-1990s, but he recovered and returned to music in 2002.

He was also an avid painter and photographer of jazz culture and Black history. His images were included with some of his albums and collected in a book published in 2015.