As a boxer, Rubin "Hurricane" Carter, who has died aged 76, was a middleweight Sonny Liston, an ex-convict whose only skill seemed to be inflicting hurt, which made him all the more intimidating to opponents. But Carter was a more flamboyant public figure than Liston and in the racially charged atmosphere of Paterson, New Jersey, in 1966, that was a dangerous thing. His biggest fight turned out to be against his conviction for a triple homicide in a Paterson bar, a fight which over the course of nearly 18 years in prison saw him transformed from street thug into a public symbol of racial injustice.

The campaign attracted celebrity backers and spawned a Bob Dylan song, Hurricane, released in 1975, which became its theme. It led to Carter's conviction being quashed, and, after a retrial found him guilty again, to an eventual overturning of his second conviction as well.

In 1966, a year before massive riots in nearby Newark changed its makeup forever, Paterson was a town strictly divided between races. Although the Lafayette Bar and Grill adjoined a black neighbourhood, it did not serve black people. At 2.30am on 17 June, two black men entered the bar and shot dead three people, seriously wounding another, before escaping in a new-model white Dodge Polara. Carter and John Artis had been stopped by police but let go because there was a third man in the car. But after a witness gave a more detailed description of a car with distinctive tail lights and out-of-state licence plates, the police returned to Carter. He and Artis were questioned, given inconclusive lie detector tests, and, when the shooting's survivor failed to identify Carter, released again.

Four months later, they were charged with the murders. Although there was, in the words of Carter's lawyer, "a mountain" of circumstantial evidence against them, much of it came with problems attached, due to sloppy forensic work and the possibility that witnesses had been coached retrospectively.

Most tendentious was the identification of Carter by two petty criminals, who had been offered reduced sentences in exchange for testimony. Alfred Bello had been standing lookout while Arthur Dexter Bradley tried to burgle a nearby factory. Seeing the shooters flee the bar, Bello ran inside and looted the cash register before calling police. An all-white jury found both men guilty, but recommended against the death penalty; Carter was sentenced to life in prison.

Born in nearby Clifton to Bertha and Lloyd Carter, Rubin grew up in Paterson, where his father, a church deacon, worked in a factory while running an ice-delivery business. A strict disciplinarian, he turned Rubin in to the police when, at the age of nine, he stole clothes from a store. Moved to a school for problem students, Rubin was 11 when he stabbed and robbed a man he later said tried to abuse him.

He spent the next six years in and out of a state home before escaping and joining the army at 17. He took up boxing but after 21 months was discharged as unfit after committing multiple disciplinary offences. Returning to New Jersey, he was re-arrested and returned to a home for older boys. Paroled in March 1957, within a few months he was convicted of three muggings and sent to prison.

There he resumed boxing, and days after his release in 1961 had his first professional fight, winning a split decision and a purse of $20. Carter's main weapon was a ferocious left-hook, but his reliance on it left his jab insufficient. He specialised in early knockouts, but was in perilous territory as fights went longer.

His record was 17-4 when, in 1963, he surprised welterweight champion Emile Griffith with a first-round knockout. Two more wins, including an impressive decision over future heavyweight champ Jimmy Ellis, led to a title shot against the middleweight champion Joey Giardello, who controlled the 15-round fight and won a unanimous decision.

In 1965, Carter fought twice at the Royal Albert Hall in London, beating Harry Scott by a technical knockout, and then losing the rematch on the referee's decision a month later, after knocking Scott down in the first round. Far from being "the number one contender for the middleweight crown" as the Dylan song had it, at the time of his conviction he had triumphed in only five of his last 12 fights.

In prison Carter was far from a model inmate, but in 1971 he acted to defuse a prison riot and may have saved the life of a prison guard. He worked on appeals, and on a biography, The Sixteenth Round (1974). Copies sent to celebrities such as Muhammad Ali and Dylan attracted support, and after Bello and Bradley recanted their identifications, in 1976 the state supreme court overturned his conviction. At his second trial, prosecutors alleged a new motive, revenge for the murder of the black owner of another bar by the white man who had sold it to him; the dead man was the stepfather of one of Carter's friends. But at trial Bello recanted his recantation, and two of Carter's alibi witnesses also recanted. The jury, which included two black men, convicted him again.

While free on appeal, however, Carter attacked a woman whom Ali had sent to him to help with fundraising, and that cost him much support. The birth of his second childtwo days after the trial ended did not stop his wife, Mae Thelma, filing for divorce after learning of his romances with supporters. Carter had attracted a group from a Toronto commune, who worked tirelessly on his behalf.

Numerous appeals failed until, in 1985, a federal judge ruled that the revenge motive had "fatally infected" the trial, and that prosecutors had withheld information about Bello's uncertain testimony. Artis had been paroled in 1981, and since Carter might be eligible soon, after losing appeals New Jersey declined to prosecute a third time. In 1985 Carter was freed.

He moved to Toronto, married the head of the commune, Lisa Peters, and became executive director of the Association in Defence of the Wrongly Convicted, but he eventually left Peters and the commune. In 1999 Carter was played by Denzel Washington in a film, Hurricane, directed by the Canadian Norman Jewison. It was much derided for simplifying or misrepresenting much of the story. In 2004 Carter broke with AIDWYC and started his own group, Innocence International.

He was diagnosed with prostate cancer in 2011, and produced another biography, Eye of the Hurricane, with a foreword by Nelson Mandela. In February he asked in the New York Daily News for the case of a Brooklyn man, David McCallum, imprisoned since 1985 for murder, to be reopened.

He wrote: "If I find a heaven after this life, I'll be quite surprised ... To live in a world where truth matters and justice, however late, really happens, that world would be heaven enough for us all."

He is survived by a daughter and a son from his first marriage.

• Rubin Carter, boxer, born 6 May 1937; died 20 April 2014