Nelson Mandela. An activist from an early age. Nelson Mandela was born on July 18, 1918, in Transkei, South Africa. Becoming actively involved in the anti-apartheid movement in his 20s, Mandela joined the African National Congress in 1942. For 20 years, he directed a campaign of peaceful, non-violent defiance against the South African government and its racist policies. Mandela made it through 27 years of prison .