John Allison Strachan Marr was born in Knysna and was educated at Rondebosch Boys' High School. His father was the first doctor at Knysna. He graduated in medicine at the University of Cape Town and spent four years in postgraduate training in England, obtaining the Conjoint Board Diploma in 1933, and the FRCS in 1934. When Marr returned to South Africa he spent three years as assistant to Professor Saint, Professor of Surgery at the University of Cape Town, and then practised in Cape Town until 1963 when he was forced to retire because of ill-health. He died at his home in Knysna in 1968 at the age of 64, and his wife and four children survived him.