Nelson Mandela was motivated to fight against apartheid in South Africa due to firsthand experiences with racial discrimination and injustice. His activism began in earnest during his involvement with the African National Congress (ANC), where he sought to dismantle the oppressive policies that disenfranchised the black majority. Mandela's commitment was further strengthened by events like the Sharpeville Massacre, which spurred widespread outrage. His imprisonment only deepened his resolve and galvanized international support against apartheid, leading to his pivotal role in South Africa's transition to a multiracial democracy.