Nelson "Nana” Mahomo was born in 1930 in the Orange Free State, the son of a Dutch Reformed clergyman, he attended Kroonstad High School in the late 1940s. Sympathetic to the Africanist group within the African National Congress (ANC), he resigned in late 1954 from the executive committee of the Transvaal Youth League in protest against the expulsion of P. K. Leballo from the league.
After working for some time as a clerk for Arthur Blaxall and attempting a business venture with Joe Molefi, Mahomo went to the University of Cape Town to start a law degree in 1957.
In April 1959 he was elected secretary for culture in the PAC. With other Africanists he helped build a Pan Africanist Congress (PAC) organization in and around Cape Town, recruiting "task forces" of youthful activists and soliciting support from sympathetic whites. Delegated with Peter 'Molotsi to go abroad as a PAC representative before the PAC antipass campaign, he was member of the national executive committee of the Pan Africanist Congress and one of its chief representatives abroad after 1960. he left South Africa on March 20, 1960.
He later represented the PAC in the United Front and traveled extensively on political missions. For a period in the mid-1960s in Britain he edited a magazine called Crisis and Change.
In 1968 he earned a master's degree in political science from the Massachusetts Institute of Technology, and later he produced two widely-acclaimed films: "End of the Dialogue" and "Last Grave at Dimbaza."