Gerry Conlon, who was wrongly convicted of the 1974 IRA Guildford pub bombing, has died aged 60, his family have announced.
Mr Conlon and the rest of the Guildford Four served 14 years of a life sentence for the attack which killed five people and injured 65, before their convictions were overturned in 1989.
He was later played by Daniel Day-Lewis in the film In The Name Of The Father.
Mr Conlon's family issued a statement through his lawyer Gareth Peirce.
It said: "This morning we lost our Gerry.
"He brought life, love, intelligence, wit and strength to our family through its darkest hours.
"He helped us to survive what we were not meant to survive.
"We recognise that what he achieved by fighting for justice for us had a far, far greater importance - it forced the world's closed eyes to be opened to injustice; it forced unimaginable wickedness to be acknowledged; we believe it changed the course of history.
"We thank him for his life and we thank all his many friends for their love."
Mr Conlon died in his home in the Falls Road area of Belfast after a lengthy illness.
Alex Attwood, SDLP Stormont Assembly member for the area, paid tribute to him.
"He'd given an awful lot but yet had so much more to give," Mr Attwood said.
"What he learned from his time in prison and campaign for release was the importance of not only raging against his own injustice but fighting for those who had also suffered miscarriages of justice."
Mr Attwood added: "He's now with his dad and his mum."
Mr Conlon's father Giuseppe, who was jailed as part of a discredited investigation into a supposed bomb making family - the Maguire Seven, died after five years in jail.
His mother Sarah, a tireless campaigner for their freedom, died in 2008, aged 82.
Sinn Fein president Gerry Adams expressed his shock and deep sadness at the news.
"Gerry and his father Giuseppe were two of the most infamous examples of miscarriages of justice by the British political and judicial system," Mr Adams said.
"Their story was told graphically in the film In The Name Of The Father.
"To his family and friends I want to extend my sincere condolences."
In 2009 Mr Conlon wrote about the personal and emotional battles he suffered as a result of his incarceration and fight for freedom.
He suffered two breakdowns, attempted suicide and became addicted to drugs and alcohol following his release.
Mr Conlon also only began enduring nightmares after securing freedom.
"The ordeal has never left me," he said.
The jailing of Conlon and the other members of the Guildford Four - Paddy Armstrong, Paul Hill and Carole Richardson - is considered the biggest miscarriage of justice in British legal history.
They were jailed for life in 1975 for the devastating attack on the Horse and Groom pub in the Surrey town which killed four soldiers and a civilian.
But they were freed in October 1989 after the Court of Appeal quashed their sentences amid doubts raised about the police evidence against them.
An investigation by Avon and Somerset Police found serious flaws in the way Surrey Police handled the case.
As he emerged free from the Court of Appeal Gerry Conlon declared: "I have been in prison for something I did not do. I am totally innocent."
In July 2000 Prime Minister Tony Blair became the first senior politician to apologise to the Guildford Four.
Ireland's Foreign Affairs Minister, Eamon Gilmore, also extended his condolences.
"I am saddened to hear of the death of Gerry Conlon and send my condolences to his family and friends," the Tanaiste said.
"Mr Conlon suffered a grave miscarriage of justice along with his father, Giuseppe, Paul Hill, Carol Richardson and Paddy Armstrong.
"In later years Gerry drew from his experiences to campaign on behalf of others with the group Miscarriages of Justice Organisation.
"His loss will be felt both within the community in west Belfast and across the world with all those who work in pursuit of justice."
Speaking at an austerity protest in London's Parliament Square today, Labour MP Jeremy Corbyn (Islington North) began his address on equality by paying tribute to his "great friend" Mr Conlon.
He said: "He stood for justice despite having 14 years of his life taken away from him while he suffered in prison.
"What a great man, what an example for all of us."