Washington grew up with a constant fear of violence. The middle child of his parents’ three sons, he was born in 1981, at the beginning of an era plagued by crack cocaine, gang warfare and police brutality that culminated a decade later in the Rodney King riots. The first house he lived in, on 74th and Figueroa in South Central, was, he said, ‘‘deep in the hood.’’ (At one point, Rickey found the body of a prostitute in the backyard.) When he was 3, his parents divorced, and his mother, a chemistry teacher, moved to a better part of South Central. Soon Rickey Washington left, too, moving to Inglewood, and Kamasi split his time between the two homes. Both neighborhoods were a considerable step up from 74th and Figueroa, Kamasi said, but still ‘‘there were gunshots and sirens every night.’’

A gifted student in math and science, Washington was at once scared of the gangs and enamored of them. The Bloods and the Crips had emerged after the decline — or destruction, as many in South Central would say — of nationalist organizations like the Black Panther Party and exerted an almost irresistible mystique. Some of Washington’s friends in junior ­high school carried guns, and he flirted with gangster style and speech. ‘‘I don’t think my parents understood how off I was,’’ he recalled. What dispelled the glamour of the gangs for him was ‘‘The Autobiography of Malcolm X.’’ He was given a copy by a group of men who visited his school; they were from a nationalist organization called Ujima, Swahili for the principle of collective work and responsibility. ‘‘I saw that these ideas weren’t random, that there was a force behind them,’’ Washington said. ‘‘I realized I didn’t want to be a part of our self-destruction. I wanted to be a positive force in the world.’’

His turn to jazz was hardly unexpected. ‘‘Kamasi was hearing ‘A Love Supreme’ before he even knew what he was listening to,’’ his father told me. He started out on drums at 3 and began studying the clarinet at 9. But Kamasi says he mostly listened to hip-hop until he was 11, when a friend of his older brother gave him a mixtape of Art Blakey and the Jazz Messengers with the trumpeter Lee Morgan. (That friend, Lamar Van ­Sciver, is now a hip-hop and R&B producer.) ‘‘That’s when I finally got into jazz,’’ he said. ‘‘All of a sudden, I became aware of all this music I had around me at home.’’ He studied his father’s vinyl collection and taught himself to play Wayne Shorter songs on soprano saxophone.

At 13, Washington announced to his father that he wanted to be a jazz musician. To test his seriousness, Rickey asked his son to sing a Charlie Parker solo. (‘‘I knew if you couldn’t sing it, you couldn’t play it,’’ Rickey said.) Kamasi sang the head and solo of Parker’s 1951 bop classic ‘‘Blues for Alice’’ note for note. His father’s reward was a Conn 6M alto saxophone, the same model Parker played. He played the alto in church for nearly a year, then switched to tenor — his father’s. ‘‘He took my tenor!’’ Rickey said. ‘‘A Selmer Mark VI, the best saxophone they make. He didn’t realize how valuable it was.’’ It’s the only tenor Kamasi has ever played.

Coltrane became his obsession. His favorite record was ‘‘Transition,’’ a defining work of Coltrane’s classic quartet. It was avant-­garde yet still melodic, exhilaratingly expressive but never chaotic. ‘‘He was just treading a line in a way that was powerful,’’ Kamasi said. ‘‘ ‘Transition’ was like the rarest of the rare steaks without being raw. You could still eat it.’’ He modeled himself on Coltrane, not just his sound but also his legendary practice regimen — as long as 12 hours a day, with sometimes hours spent on a single scale or even a single note. Washington was soon averaging nine hours a day; as if to summon the master’s spirit, he often worked on Coltrane tunes. He and Cameron Graves, who is now his pianist, ‘‘used to compete with each other to see who could practice the most.’’ It was a monkish existence, Washington said. ‘‘Becoming a musician is a strange thing. It’s not all cupcakes and ice cream. You’re trying to master an instrument, and you sometimes can’t tell if you’re getting better. You love it, but you also hate it.’’

It was not long after he took up the tenor sax that Washington met another jazz ‘‘guard’’: Reggie Andrews, a music teacher at Locke High School in Watts. Andrews, whose former students included Rickey Washington, had grown frustrated that the city’s magnet schools had poached the best young musicians — including Kamasi Washington, who was discovering Prokofiev and Stravinsky at Alexander Hamilton High School, a prestigious musical academy near Culver City. Andrews began visiting nearby schools and asking the music teachers to identify their best pupils. His idea was to pick them up in his van after school, drive them to Locke and turn them into a group. He called it the Multi-School Jazz Band, and before long it was performing throughout the city. I drove with Washington to Locke, a squat structure surrounded by a wire fence that made it look more like a prison than a school. ‘‘The amazing thing is that white kids were coming down to Locke to rehearse because the band was so good and they wanted to be in it,’’ he remembered. ‘‘It was kind of ironic, since we were being bused to their schools.’’ Seeing young whites flock to Locke gave Washington a taste of power, an awareness of the cachet he possessed as an African-American musician. In spite of the ‘‘denial of our humanity,’’ he realized, ‘‘everybody wants to dress and talk like us.’’