Nelson Mandela joined the African National Congress in 1944. That year he helped establish the ANC Youth League with Walter Sisulu, Oliver Tambo and other younger activists.
The Youth League promoted a more assertive mass-based approach to opposing racial discrimination. Its programme influenced the ANC’s later campaigns against apartheid laws, including the Defiance Campaign of 1952. Mandela became increasingly prominent within the organisation as South Africa’s racial laws became more restrictive.
Mandela’s ANC membership began before the formal apartheid system was introduced in 1948, although racial segregation and white minority rule already existed. He remained associated with the movement for the rest of his public life and served as its president from 1991 until 1997.