Available on DVD: “Marley”

A thorn in the side of the Jamaican reggae superstar Bob Marley was his lack of a black audience in the United States even at the height of his career. But in September 1980, eight months before his death at 36, that began to change with a triumphant engagement at Madison Square Garden, where he and his band, the Wailers, opened for the Commodores. The next day, according to Marley, a riveting two-and-a-half-hour documentary biography directed by Kevin Macdonald, he collapsed while running in Central Park. When examined, he was found to have inoperable, late-stage cancer.

Three years earlier Marley had chosen to ignore the danger signs when a malignant melanoma was discovered in one of his toes. He refused to have it treated — it probably would have meant an amputation — because he would no longer be able to dance onstage.

That stubbornness says a lot about Marley, whose obsessive drive seems only to have accelerated the more famous he became. He was so immersed in writing that he was said to sleep only four hours a night. Even when gravely ill he displayed a superhuman energy and willpower. Two of his children — David, aka Ziggy, now 43, and Cedella, now 44 — remember him as a disciplinarian who was hypercompetitive when they played games. All together he had 11 children from seven relationships.

His wife, Rita, who performed with his backup singers, the I Threes, made her peace with his womanizing and acted as his doorkeeper. Marley was not an aggressive sexual predator. A shy man, he was besieged with female adoration; women simply fell into his lap.

Though made with the cooperation of the Marley family, the film is far from a hagiography; and while stocked with musical sequences, it is not a concert film. Few if any of his songs are heard all the way through. Marley is a detailed, finely edited character study whose theme — Marley’s bid to reconcile his divided racial legacy — defined his music and his life.

The opening scene, on the coast of Ghana, shows what is called "the door of no return," through which countless Africans passed on their way to slavery. When he became a star, Marley passionately embraced his African roots, performing in Gabon (although it was a dictatorship) and at the ceremonies in which Rhodesia became Zimbabwe.

Born in an impoverished village in the Jamaican hills, Marley was brought up in a tin-roofed shack. He was the son of a young black woman, Cedella Marley Booker, who had a passing relationship with the much older Norval Marley, a British Army man of mixed race who was considered a white Jamaican. (He is seen in the film on horseback in a photograph.)

Because of his racially mixed parentage Bob Marley found himself a social outcast. At 12 he moved to the seething, poor Trench Town district of Kingston, where he soaked up music on the radio, learned the guitar and found a father figure in Clement Dodd, a record producer known as Sir Coxsone, who owned a recording studio. Marley was 16 in 1962, when his first single, Judge Not, set a righteous tone for what was to come.

The movie does a fascinating job of showing how, almost by accident, reggae evolved out of ska, Jamaica’s popular dance music of the time. American pop-soul, especially the music of groups like the Temptations, was also a major influence. Marley and the Wailers’ ska rendition of A Teenager in Love from Dion and the Belmonts is heard. Another hybrid, fraught with even more significance, is Selassie Is the Chapel, a rewritten version of the American hit Crying in the Chapel. This version praised Marley’s ultimate father figure, Haile Selassie, the Ethiopian emperor whom Rastafarians regarded as a deity. Mortimer Planno, a drummer and Rastafari elder, was also an important mentor.

Once he embraced Rastafarianism, Marley and his inner circle maintained a self-disciplined regimen of exercise, training and abstemiousness, except for marijuana, which was considered a sacrament.

Chris Blackwell, the British record executive who signed and groomed Marley and the Wailers, comes across as a cool cookie who promoted them as "a black rock act" and created discord after they weren’t paid for their work on a grueling promotional tour. Two members quit, including Neville Livingston, known as Bunny Wailer, the movie’s most frequent commentator. (He would change his mind and rejoin the group.)

At this point the film becomes more of a career biography in which Marley, in spreading his global message of "one love, one heart," exhibits a messianic sense of himself. His symbolic importance put him at risk, and he narrowly avoided an assassination attempt in 1976. The culmination of his drive to be a peacemaker was his April 1978 One Love Peace concert, since called the Third World Woodstock, at a Kingston stadium. There he joined the hands of the rival political leaders Michael Manley and Edward Seaga.

His music has only grown in importance since his death. Bob Marley and the Wailers’ 1984 anthology, Legend, has sold 25 million copies worldwide, and his music and image proliferated at Arab Spring demonstrations. You have only to listen to him or see a filmed performance to understand the potency of a voice synonymous with fervent hope.