Justice Hannes Fagan was born in Cape Town and studied law at UCT and Oxford University before beginning his practice as an advocate in 1952. He was a member of the Cape Bar Council for many years. In 1959, he served as a member of the Rotary Club of Cape Town and was involved in youth activities, student-exchange programmes and the eradication of alien vegetation in the Cape Peninsula. In 1974, he was appointed as acting judge in the Cape Provincial Division and three years later he became a permanent judge. He served as a member of the National Institute for Crime Prevention and Rehabilitation of Offenders. In 1978, Justice Fagan became chairman of the Board of the Institute of Criminology at the University of Cape Town.