Born at Dunedin, New Zealand on 1 October 1893, the eldest son of (Sir) Louis Barnett, FRCS and his wife Mabel Violet Fulton. He was educated at Christ's College, Dunedin, and the Otago Medical School, where he graduated in 1920. His student years were interrupted by the war, when he volunteered for active service and fought in the landings at Gallipoli in 1915. From 1920 to 1925 he was in England, and acted as resident medical officer at the Middlesex Hospital. After taking the Fellowship he returned to practise in Dunedin, where he was appointed assistant surgeon to the Dunedin Hospital and lecturer in clinical surgery at Otago University. He was elected a Fellow of the Australasian College in 1936. During the war of 1939-45 he served on the New Zealand war pensions appeal board. Barnett married in 1920 Flora Chalmers, who survived him with two sons and three daughters; a third son had been killed in the second world war. They lived at 83 Stafford Street, Dunedin. He died suddenly, while driving his car in Dunedin, on 14 July 1950, aged 56. Barnett was of quiet disposition, but a keen player of games - rugby football when young, and later golf and bowls.