Born in 1926 Mavuso worked at different times as a messenger and a shopkeeper. He was a member of the African National Congress national executive committee from 1955 to 1956 and was active in the Alexandra branch in Johannesburg. Banned a number of times under the Suppression of Communism Act, he was a defendant in the Treason Trial from December 1956 until charges were dropped against him in December 1957.