Upon returning to Rhodesia, Madzimbamuto became active in nationalist politics. First he joined the recently founded City Youth League. When it merged with the African National Congress in 1957, he became chair of the ANC's Highfield branch. He was first detained in 1959 and though occasionally released for short periods, was not fully released until 1963. Then he was soon re-arrested as a member of the Zimbabwe African People's Union Central Committee. Stella Madzimbamuto challenged his continued detention in the landmark legal case Madzimbamuto v Lardner-Burke on the grounds that Rhodesia's Unilateral Declaration of Independence in 1965 was invalid. She lost in Rhodesian court, and though she won in the Judicial Committee of the Privy Council in 1968, Madzimbamuto was not released until 1974. They had other children during this period, whose names reflect their parents' growing desperation: Chipo ("Gift"), Tambudzai ("They are troubling us") and Tafirenyika ("We are dying for the country"). During imprisonment, Madzimbamuto earned a law degree via correspondence from the University of London. In 1969, he was declared Amnesty International Prisoner of the Year.
