Early in 1963 a young black man called James Edward Orange was working as a chef in Birmingham, Alabama. Just a year out of high school, Orange was not involved in the civil rights demonstrations that were beginning to convulse the city. But when a young woman invited him to a movement meeting, where she was going to sing in the choir, he was happy to get at least a little involved. As he put it later: “We were to meet afterwards and go and have a soda and talk.”

Instead, afterwards he met movement leaders and volunteered to go on a march and get arrested. He spent the next five years working with Martin Luther King, and the rest of his life working for social justice. He would be arrested more than 100 times in total.

Orange grew up in Birmingham, the third child of seven children. His father was a union man, and his mother supported the civil rights movement.

By the time he got to the mass meeting, the church was already fairly full. Orange took a spare seat near the front. The speaker that night was the Rev Ralph Abernathy, Martin Luther King’s deputy and a powerful, witty preacher. Orange was deeply moved. At the end of the service he discovered that some seats had been spare because they were reserved for volunteers willing to go to jail. He agreed to lead a group to picket a shop the next day. He was so new to the movement that he did not realise that pickets were supposed to stand outside the store — his group marched around inside the store carrying banners before the police arrested them.

In 1963 Birmingham became the focal point of the civil rights movement. The city’s police chief, Eugene “Bull” Connor, set police dogs and turned fire hoses on demonstrators. The Klan bombed the main movement church, the one that Orange had attended, killing four children.

Orange was one of the hundreds of young people who marched and regularly went to jail. The combination of dignified protesters, white violence, an outpouring of national sympathy and global criticism of US racism persuaded President Kennedy to introduce the civil rights legislation that would lead to the Civil Rights Act of 1964, which outlawed segregation in the US.

After Birmingham, Orange joined King’s organisation, the Southern Christian Leadership Conference, full time. Although the media focused on King, much of the SCLC’s work was done by young field staff, such as Orange, who lived and worked in the rural South.

In 1965 he organised protests in the small town of Marion, Alabama. King was leading demonstrations calling for voting rights in nearby Selma, where the movement was struggling to make progress. After Orange was arrested, word spread that he might be killed. Selma volunteers joined a march in Marion — a march which led to the murder of a young man named Jimmie Lee Jackson by an Alabama state trooper. The SCLC called for a march from Selma to Montgomery in Jackson’s memory, to draw attention to the continuing racism in the South. State troopers attacked the marchers. TV networks interrupted their programmes to show some of the violence. One viewer, Lyndon Johnson, was particularly appalled. He signed the Voting Rights Act soon after.

In the eyes of the media and many politicians, that was the end of the civil rights movement. But for many of those involved, it was just the beginning. In Orange’s case, he continued to work for the SCLC as it began to focus on the problems of urban poverty and housing segregation, and he followed King to Chicago.

The SCLC struggled to adapt its tactic of non-violent protest to Northern cities. On his first trip to the ghetto Orange came across a fight between members of two notorious gangs. Orange, 6ft 3in tall and heavy set, reasoned with the combatants. In an interview he recalled saying: “Hey man, brothers ain’t got no business fighting. Y’all oughta be trying to fight the system and here y’all fighting each other.” He ended up with a broken nose.

Over time, however, Orange did persuade some of the city’s notorious street gangs to join the campaign. He was also involved in the SCLC’s ambitious and controversial Poor People’s Campaign in 1968, which brought thousands of homeless black Americans to camp outside the White House. During the campaign he joined King in Memphis in support of striking sanitation workers. By now experienced in dealing with gangs, Orange met a gang that tried to extort protection money from the movement. He was present at the Lorraine Motel in Memphis when King was murdered in 1968.

Like many activists, Orange continued his work for social justice long after the death of King. He knew no other profession and he judged that the movement’s legislative victories had done little to improve the lives of black workers. In 1970 he moved to Atlanta as a regional co-ordinator with the AFL-CIO, the US’s main trade union organisation. In 1977 he led workers to a famous victory for union recognition at the large textile firm J. P. Stevens.

Orange worked in the union movement, based in Atlanta, until the end of his life. As a black civil rights campaigner, he had a double agenda — to win union rights for workers, and to win representation for black workers within the union movement. In interviews towards the end of his life he expressed himself delighted at the progress within the unions — most unions were segregated during the 1960s but by the end of the 20th century they were champions of diversity. But Orange worried about the future of affirmative action and workers’ rights, and called on labour organisations and civil rights groups to work together. In 1999 he helped to organise the march of unionists and environmentalists in the so-called “Battle in Seattle” in protest at the policies of the World Trade Organisation.

He is survived by Cleophas, known as Cleo, his wife of 39 years, three daughters (another daughter died last year) and a son.

The Rev James Orange, US civil rights campaigner and pastor, was born on October 29, 1942. He died from post-operative complications on February 16, 2008, aged 65