Born in Louis Trichardt, Nkondo was a lifelong activist with the ANC.
He was a high school teacher at Lamula High School in Meadowlands, Gauteng and eventually became the chairman of the Soweto Teachers Action Committee before being suspended for educating against apartheid.
A year after the formation of the Azanian People's Organisation (AZAPO) in 1978, in September 1979, at its conference in Roodepoort the national executive was formed with Nkondo as its president.
Nkondo was the chairman of the National Education Union of South Africa and in 1984, he was one of the UDF's leaders that were tried for treason.
Following independence, Nkondo became South Africa's High Commissioner in neighboring Namibia.