 Nyanda joined Umkhonto we Sizwe (MK), the military wing of the African National Congress, in 1974, and served as a field commander during the liberation struggle against the South African government in the 1980s.He was appointed MK Chief of Staff in 1992, and served on the Transitional Executive Council which oversaw the change of government in 1994.Major General Nyanda became part of the South African National Defence Force, into which MK was incorporated in 1994, and served successively as Chief of Defence Force Staff (1994–1996), General Officer Commanding Gauteng Command (1996–1997), Deputy Chief of the South African National Defence Force (1997–1998), and Chief of the South African National Defence Force (1998–2005).