Mr. Cowell, who had homes in Upper Marlboro, Md., and Camden, Del., expanded the vocabulary of jazz with an approach that was simultaneously cerebral and earthy. He had more than 30 recordings as a leader and appeared on recordings and in performance with countless major jazz figures.
In the 1960s, when he came to prominence, he worked with trumpeter Miles Davis and saxophonist Rahsaan Roland Kirk and was a member of an influential group led by drummer Max Roach. A prolific composer as well as a pianist, Mr. Cowell wrote several tunes for Roach’s 1968 album, “Members, Don’t Git Weary,” including “Equipoise” and “Effi,” that have been widely performed by others.
Mr. Cowell had one foot firmly in the jazz tradition and another in the avant-garde. He often performed standards and jazz classics, but in new and unexpected ways. In one case, he slowed down the headlong gallop of Charlie Parker’s bebop classic “Anthropology” and reimagined it as a ballad.
Reserved and dignified in his manner, Mr. Cowell could play the piano with a blend of exuberance and introspection. He jumped from James P. Johnson’s “Carolina Shout” from the 1920s to ruminative, harmonically dense original works drawn in equal parts from classical music and experimental jazz.
“Always unfolding dramatically,” Mr. Cowell’s music “is never pretentious, never afflicted with arcane, elitist self-indulgence posing as cosmic significance to be comprehended by only a chosen few,” Hartford Courant jazz critic Owen McNally wrote in 2013.
Mr. Cowell’s first album, released in 1969, was titled “Blues for the Viet Cong,” and his music often suggested social ideas or elements of Black history and pride. His 2015 album, “Juneteenth,” was a suite of original compositions for solo piano inspired by the African American struggle for empowerment and freedom.
During the 1970s, Mr. Cowell helped found Collective Black Artists Inc., an effort to give jazz musicians greater control over their compositions, recordings and performance venues. With trumpeter Charles Tolliver, a longtime musical collaborator, he launched Strata-East, an independent, artist-owned record label. Mr. Cowell made solo recordings for the label and collaborated on other albums with Tolliver and saxophonist Clifford Jordan. A 1975 recording, “Regeneration,” blended Western and African instruments in imaginative ways.
At the same time, Mr. Cowell was exploring other musical concepts, including the “Piano Choir,” a grouping of up to nine pianists and other musicians on a single stage, creating stunning sonic effects. He developed the idea after learning that James Reese Europe, an African American orchestra leader of the early 20th century, once had a concert for 14 pianos.
“I thought it was a possibility that hadn’t been exploited in modern jazz,” Mr. Cowell told The Washington Post in 2000.
He worked with a wide array of musicians, including saxophonists Sonny Rollins, Gary Bartz and Stan Getz, vibraphonist Bobby Hutcherson and drummer Roy Haynes. For several years, he was the pianist with the Heath Brothers band, featuring saxophonist Jimmy Heath, and made a number of recordings with them. He experimented with electronic instruments, including computers that altered the piano’s pitch and percussive intensity.
In 1981, Mr. Cowell began a long teaching career, first at the City University of New York’s Lehman College and, beginning in 2000, at Rutgers University in New Brunswick, N.J., where he was director of the jazz program.
From 1989 to 1999, Mr. Cowell released 13 jazz albums, and he continued to write music, including a piano concerto, orchestral works, chamber music and compositions for solo piano.
But his appearances at traditional jazz venues gradually became more infrequent, making his occasional performances with other members of the Rutgers jazz faculty, such as drummer Victor Lewis, saxophonist Ralph Bowen and guitarist Vic Juris, must-see events for jazz fans.
“I do take gigs from time to time, though I kind of dropped out of the club scene,” he told the Newark Star-Ledger in 2006. “I’d rather play a concert, reach maybe 1,000 people, which is more people than you’ll see at a small club in a week.”
Stanley Allen Cowell was born May 5, 1941, in Toledo. He parents owned a restaurant and a hotel that was a frequent gathering spot for visiting Black musicians.
Mr. Cowell showed early promise on the piano, and at age 6, he met Toledo native Art Tatum, often considered the greatest piano virtuoso in jazz history. Mr. Cowell marveled at Tatum’s ability and was inspired to pursue music professionally.
While leading jazz combos on the side, his studies focused on classical music. After graduating from the music conservatory at Ohio’s Oberlin College in 1962, he studied at several other colleges, including Austria’s Mozarteum University Salzburg. In 1966, he received a master’s degree in classical piano performance from the University of Michigan, then moved to New York to pursue his interest in jazz.
His marriages to Effi Slaughter and Victoria McLaughlin ended in divorce. Survivors include his wife of 32 years, the former Sylvia Potts, of Upper Marlboro; their daughter, Sunny Cowell, a musician and lawyer, of Baltimore; a daughter from his second marriage, Sienna Cowell of Chesapeake, Va.; a sister; and two grandchildren.
After retiring from Rutgers in 2013, Mr. Cowell began to raise his profile as a performer, including a celebrated week-long engagement at New York’s Village Vanguard in 2015. In October 2019, Mr. Cowell appeared for several days at Baltimore’s Keystone Korner jazz club with a quintet — and his daughter Sunny on vocals. The resulting live album was released last month.
An earlier version of this story omitted the name of Stanley Cowell’s first wife, Effi Slaughter. She was later married to former D.C. Mayor Marion Barry.
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