In January 1940, Sisulu moved to
Johannesburg, where she began her long nursing career as a trainee in the non-European section of the Johannesburg General Hospital. Her interest in politics grew through her association with
Walter Sisulu, a real estate agent and activist in the
African National Congress (ANC), who courted and then married her. She began attending ANC meetings not as a member but as his companion.
Ellen Kuzwayo, another of the few women present at such meetings, later remembered her as "a kind hostess who served the committee members of the congress with tea after long and intense meetings". According to Pippa Green, she joined the
ANC Women's League in 1946.''' However, her husband's political activities made Sisulu the family's main breadwinner, and she did not actively participate in ANC activities until the 1950s, by which time the
National Party had introduced its programme of institutionalised
apartheid.'''''' and in October 1958 she was arrested for the first time and charged for participating in another women's march against
pass laws. In the early 1960s, she was involved in an ANC scheme to recruit nurses as volunteers to relocate to newly independent
Tanganyika, a personal favour from
Oliver Tambo to
Julius Nyerere. Meanwhile, Sisulu's husband was a defendant in the 1956–1961
Treason Trial, and their home became a target for
Security Branch attention and raids.''' After the 1960
Sharpeville uprising, the apartheid government banned the ANC and several associated organisations; shortly afterwards, the ANC announced the inauguration of armed struggle. Her husband, a founder of
Umkhonto we Sizwe, went into hiding underground in 1963. On 19 June of that year, Sisulu became the first woman to be detained under the so-called 90-Day Detention Law: the recently enacted
General Laws Amendment Act, 1963 allowed police to detain activists incommunicado indefinitely and
without charging them. The respite lasted less than a year before she was arrested and served with another banning order, her fifth, in June 1982; that order was part of a more general crackdown effected in Soweto during commemorations of the
1976 Soweto uprising. Nonetheless, throughout this period, Sisulu remained a prominent figure in the resistance movement, notable for her focus on civic organising on a national rather than local scale. She was particularly influential in the preparations for the establishment of the
United Democratic Front (UDF), a
popular front against apartheid that was launched in 1983, and in a protracted campaign to revive FEDSAW. From the 1970s, she was active in the political mentorship of younger women activists such as
Jessie Duarte and
Susan Shabangu; Duarte later said that Sisulu's protégés considered themselves "MaSisulu's girls", and she was instrumental in the foundation of a Soweto-based underground ANC cell for women, named
Thusang Basadi ("wake up women"). and in July 1983 she attended meetings of the national steering committee that was preparing for the national launch of the UDF. She and her co-accused, activist Thami Mali, were accused of having conspired to further the aims of the banned ANC in connection with their role in planning the funeral of Rose Mbele, an ANC Women's League Stalwart. The funeral had taken place months earlier – on 16 January 1983 in a church in Soweto – and the charges were widely viewed as a justification to detain Sisulu ahead of the UDF's launch. she later said that they were like mother and son, and he did not object to Sisulu's political activities, which continued in earnest. However, in the 1980s, their relationship grew tense as Sisulu attempted to curb Mandela United's excesses. In later years, because of their husbands' stature, the press often contrasted Madikizela-Mandela and Sisulu as opposing models of female activism, comparing Sisulu's cool-headed maturity with Madikizela-Mandela's "rage and charm". Meanwhile, Asvat was an unpopular figure both with the state and with conservative residents of Soweto; in 1987, Sisulu was with him when he narrowly escaped a knife attack, and in December 1988, they worked without water or electricity after the supply to their surgery was cut off. Madikizela-Mandela and her Football Club long faced rumours of having arranged Asvat's assassination, and Sisulu was publicly drawn into those accusations in 1997 .
Pietermaritzburg Treason Trial In 1984, while Sisulu was working at Asvat's surgery and awaiting the appeal of her criminal conviction, the UDF vastly expanded its national presence through an intensive campaign of opposition to President
P. W. Botha's constitutional reforms, including the
Black Authorities Act, 1982 and the
1983 Constitution.
The first elections to the
Tricameral Parliament in August 1984 were marred by a successful UDF boycott, followed by
widespread township uprisings. She and 15 others were charged under the
Internal Security Act with
treason and incitement to overthrow the government. As the only woman accused, she was held in detention alone. The ensuing
Pietermaritzburg Treason Trial opened on 21 October in the
Natal Supreme Court with the defendants' not-guilty plea, but the charges against Sisulu and 11 others were dropped on 9 December. Sisulu told press it was "a crushing victory for us". Popular uprisings continued, and Sisulu was banned again in 1986
1989–1994: Negotiations In 1989, as the
negotiations to end apartheid quickened, Sisulu embraced her public-facing role in the anti-apartheid movement. In June that year, she was granted her first
South African passport – an abrupt reversal, given that her latest banning order had been renewed only days earlier. Later that month, she led a UDF delegation on an international tour, which included a meeting with British Prime Minister
Margaret Thatcher. While in
London, she met with
Labour Party leader
Neil Kinnock and addressed a major rally of the British
Anti-Apartheid Movement. On 30 June 1989, she met with American President
George H. W. Bush in the
White House. The delegation also travelled to Sweden; to France, on the invitation of
Danielle Mitterrand; and to the ANC's headquarters in exile in Lusaka, where Sisulu provided exiled leaders with a report on conditions inside South Africa. Over the next two years, she worked at the league's downtown headquarters in
Shell House. However, she held the deputy presidency for only one term, ceding the office to
Thandi Modise at the league's next national conference in December 1993. The mainstream ANC held its own reunion in July 1991 at the
48th National Conference in
Durban, where Sisulu was elected to serve as a member of the party's
National Executive Committee. She only served one three-year term in the committee; at the
49th National Conference in December 1994, both she and her husband declined to stand for re-election to the party's leadership. During the struggle, she also found refuge at the
Albert Street Methodist Church, Johannesburg, which played a key role in sheltering activists. ==Post-apartheid political career==