Miriam Makeba, who has died aged 76, was known as Mama Africa and the Empress of African song. She was one of the most visible and outspoken opponents of South Africa's apartheid regime from the 1960s till its dismantling in the early 1990s. She was also the anti-apartheid movement's most audible spokesperson, having entered the top flight of international performers and able to sell out prestigious concert halls with a repertoire that changed little over three decades of musical evolution.

Makeba's career propelled her from township singing group to global celebrity, feted in some countries and banned from others. She was a natural and consummate performer with a dynamic vocal range and an emotional awareness that could induce the delusion of intimate contact in even the most impersonal auditorium. But her personal life was an epic tragedy of injustice, domestic upheaval, exile and torment.

Miriam "Zenzi" Makeba was born in a township suburb of Johannesburg. Her father, Caswell, was Xhosa; her mother, Christina, was Swazi. The name Zenzi (from the Xhosa Uzenzile, meaning "you have no one to blame but yourself"), was a traditional name intended to provide support through life's difficulties.

Later the family moved north to Transvaal, where Caswell worked as a clerk for Shell. Her mother was a spiritual healer who also took jobs as a housemaid. After the early death of her father, Miriam was forced to work, and for a short spell she also did housework. But she had already noticed that "music was a type of magic" that could elevate her from the poverty which surrounded her. As a young girl, her singing had been praised at the Methodist Training school in Pretoria, but what should have been the highlight of her amateur career turned to disappointment. She had been due to sing What a Sad Life for a Black Man for the visit of King George VI, but after the children had stood waiting in the rain, the royal visitor drove by without stopping to hear them.

When apartheid was introduced to South Africa in 1948, Makeba was old enough to grasp the consequences, and to see the limitations placed on the career of her heroine Dolly Rathebe, her senior by four years. Makeba gave birth to her daughter Bongi at the age of 17 and was then diagnosed with breast cancer, which was treated unconventionally, but successfully, by her mother. The first of her five husbands left her shortly after.

Her musical career progressed more smoothly. Since the turn of the century, American jazz and ragtime had been absorbed into South Africa and transposed into local forms. Combined with Anglican church hymnody, this had led to the distinctive vocal harmonic style known as mbube, practiced in many communities by "evening" or "night" choirs of enthusiastic amateurs. Following a period with the Cuban Brothers, Miriam's big break came in 1954 when she joined the Manhattan Brothers, a top band whose vocal harmonies were modelled on the American Mills Brothers and Ink Spots.

Initially, when the Manhattans travelled abroad Miriam joined a female group called the Sunbeams who became better known as the Skylarks. They recorded more than 100 songs, many of which became big hits, with Miriam singing alongside Abigail Kubeka, Mummy Girl Nketle, Mary Rabatobi and sometimes with Dorothy Masuka, who brought songs and vocal inspiration from her homeland of Northern Rhodesia (now Zambia).

Eventually, Miriam went on tour with the Manhattans, getting her first taste of the outside world visiting Rhodesia (Zimbabwe) and Congo. Playing at home she also experienced some of the most heartless and shameful aspects of the apartheid system, which she later recalled in her autobiography, Makeba My Story (1988), written with James Hall.

In 1957 she was recruited as a soloist in the African Jazz and Variety Review that toured Africa for 18 months. Then she landed the female lead role in King Kong, a legendary South African musical about the life of a celebrated boxer that played to integrated audiences and spread her reputation to the liberal white community.

The key to her international success was a small singing part in the film Come Back Africa, a dramatised documentary on black life directed covertly by Lionel Rogosin. Miriam played herself singing two songs in a shebeen. When the film was finished Rogosin invited her to attend a screening at the 1959 Venice film festival, where she became an instant celebrity. She was flown, via London, to New York appearing on television and playing at the Village Vanguard jazz club.

The calypsonian Harry Belafonte took her under his wing and guided her through her first solo recordings. African standards such as Pata Pata and the Click Song, which she first performed with the Skylarks, formed the basis of her repertoire and remained the most popular songs throughout her career. Shortly after the Sharpeville massacre in 1960, Miriam heard that her mother had died, but her own South African passport had been revoked and she was prevented from returning home for the funeral. Thus began 30 years of exile.
Her life in the US continued to unfold like a showbiz dream. She was recording and touring, and meeting all the stars from Bing Crosby to Marlon Brando: the young newcomer was also staggered to find herself appearing along with Marilyn Monroe at the famous birthday celebration for John F Kennedy.

Her first return to the continent of Africa came with a visit to Kenya in 1962. The following year she gave the first of several addresses to the UN special committee on apartheid, and South Africa reciprocated by banning her records. Shortly afterwards, she was the only performer to be invited by the Ethiopian emperor Haile Sellassie I to perform in Addis Ababa at the inauguration of the Organisation of African Unity.

In 1965 she married her old friend Hugh Masekela before flying to perform in Algeria and at the OAU conference in Accra, Ghana. Backstage at a show in San Francisco, a Kenyan student taught her a song that would become part of her standard repertoire. Called Malaika, it is a Swahili love song that she was wrongly informed was a traditional composition. In 1966 she earned a Grammy award with Belafonte.

Increasingly involved in, and identified with, black consciousness, Miriam became associated with radical activity not just against apartheid but also in the civil rights movement and then black power. In 1967, while in Guinea, she met the Black Panther leader Stokely Carmichael, who became her next husband.

Carmichael changed his name to Kwame Touré and she returned with him to his own place of exile in Guinea, the West African Marxist state whose leader, Sekou Touré, gave sanctuary to enemies of the capitalist west. In that polygamous country, Makeba eventually separated from her third husband. She turned down a proposal by the president but subsequently became the second wife to a prominent Guinean. When her beloved daughter Bongi died after a traumatic miscarriage, Miriam succumbed to a kind of "spiritual madness" that she believed she had inherited from her mother.

During her time in Guinea, Makeba became a double exile, unable to return home and unwelcome in many western countries (she was banned from France), although she collected a sheaf of diplomatic passports from sympathetic African states and enlivened several independence celebrations. She recruited a pan-African squad of top musicians who were on call to accompany her on frequent foreign trips.

She also endured some bizarre showbusiness episodes. In Denmark, a country where she had solid support, she once failed to appear for a show. She returned some years later only to be jailed for a night until the outstanding financial penalty had been paid on her behalf. There was also controversy in Tanzania over the provenance of Malaika, which several east Africans had claimed to have written. From Guinea she moved to Switzerland, where she married for the fifth time.

When Makeba played at the Royal Festival Hall, London in 1985, it was her first appearance in Britain for 11 years, and also her 53rd birthday. There she replied to the criticism that she had turned her back on the west and had gratuitously insulted white people, notably some unfortunate teachers in Jamaica who had suffered an unjustified, personal attack while watching her perform: "People have accused me of being a racist, but I am just a person for justice and humanity. People say I sing politics but what I sing is not politics, it is the truth. I'm going to go on singing, telling the truth." In 1986 she was awarded the Dag Hammarskjöld Peace Prize for her efforts.

Makeba always took time to endorse the cultural boycott of South Africa, of which she was a figurehead. As the apartheid barriers showed signs of crumbling she was embroiled in another strange episode, which saw ANC supporters boycotting her show at the Royal Albert Hall. She herself was accused of breaking the boycott by collaborating with Paul Simon on his controversial Graceland album (1986). Simon was the one being picketed for not conferring with the exile groups prior to his recruitment drive for South African session players. Makeba and Hugh Masekela gave him full support, however, and welcomed the controversy because it brought important issues into general discussion and made cultural activity even more potent.

To much of the world, Makeba had reached a level of statesmanship that verged on saintliness. She was the first choice performer at festivals as euphoria built up before and after the release of Nelson Mandela in February 1990 and the realisation that apartheid was almost over. After 30 years away, Miriam returned to South Africa to a respectful reception and performed sporadically. But the music business had moved on during her long absence and, despite working with the hot-shot producer and multi-instrumentalist Sipho Mabuse, the opportunities for giving concerts had diminished.

Many younger South Africans had no idea who Miriam Makeba was or what she had struggled for on their behalf. Others recognised her value and she was awarded an honorary degree by the University of Durban, who declared her to be a cultural ambassador for the country; and when she announced her retirement in 2005, she found that "everyone keeps calling me and saying 'You have not come to say goodbye to us!'"

So the farewell tours continued till her death in Naples, apparently from a heart attack after singing for 30 minutes in a concert supporting the movement against organised crime inspired by the writer Roberto Saviano. When Makeba was in Britain last May with her much younger eight-piece band, led by her grandson Nelson Lumumba Lee, John L Walters found her in "confident, clear-voiced form", defying the limitations placed on her mobility by osteoarthritis. Her daughter died in 1985.

Miriam Makeba, singer, born March 4 1932; died November 10 2008