Sedibe was born in 1945 in White River.[1] Around age six, her parents split up and Sedibe went to live with her uncle, Ben Sedibe, who was also an activist in the African National Congress (ANC).[1] Sedibe followed her uncle's lead and became active in the ANC by delivering leaflets and carrying messages.[1] In 1964 she became one of the first women involved in the uMkhonto we Sizwe (MK) when she joined at age 17.[2] Sedibe was sent to the Soviet Union for training at the Odessa Infantry Academy and went on to receive training on military combat and "clandestine radio communications" in 1966.[3]
Sedibe's first mission was on the Wankie Operation, where she worked as a radio operator in Lusaka between 1969 and 1971.[2] During the operations, she became the communications chief.[2] Starting in 1972, she worked in ANC branches as a secretary and chairperson and also wrote and co-edited the Voice of Women Bulletin.[2] In Lusaka, between 1976 and 1977, she worked with Zambian immigration officials to process new recruits and in 1978, she became a member of the Revolutionary Council.[2] In 1984, Sedibe was appointed to the ANC's National Executive Committee (NEC).[2] In 1990, she became the communications head for the military department of the ANC at their headquarters in Johannesburg.[2]
After returning from exile, Sedibe was part of the first group of former MK members to become integrated into the South African military in 1994.[1][4] She started working for the office of inspector general where she has focused on women's issues in the South African National Defence Force (SANDF).[1] Sedibe was promoted to the rank of major general in 1996.[5] She is considered the first black woman to hold that rank in the SANDF.[6][7]