Mansfield was born in Indooroopilly, Brisbane, son of District Court Judge Edward Mansfield and his wife Margaret Elizabeth Bird. He was educated at Toowoomba Grammar School and Sydney University, and after graduation completed his residency at the Brisbane General Hospital. He was commissioned in October 1916, and sailed from Melbourne in December. He landed at Plymouth in February 1917. He was attached to the AAMC Trg Depot at Larkhill and 2 Trg Bn at Durrington, but spent some time in the Fargo Military Hospital with tonsillitis. He was sent to France in June 1917 to 2 AGH at Wimereux, and served there until posted to 10 Fd Amb in August. He spent time in hospital again in October with a PUO, and in December after leave in England was medically examined at AIF HQ in London, and declared fit for service. He returned to France in January 1918 and was transferred to 9 Fd Amb. In March he was posted to 3 MG Bn, and served with this unit until the Armistice. During November and December 1918 he had short detachments to 38 and 39 an and to 3 PM Bn. He was evacuated to England in December 1918 with ‘ethmoiditis and atrophic rhinitis'. Presumably this was a continuation of his previous upper airway infections, and he was repatriated to Australia in January 1919. Back in Australia, Mansfield completed a further residency at the Sydney Hospital. He first set up practice in Cairns, Qld, with his brother Edward (MB ChB Edin 1914) but soon moved to Ayr, Qld, where he became Medical Superintendent of the Lower Burdekin Hospital. In 1927 he went to England to study ophthalmology. On his return in 1930 he married Nancy Mitchell Webb, who came from Orange. NSW. The couple settled in Brisbane and Mansfield was appointed to the staff of the Mater Misericordiae Hospital in South Brisbane. He retired to Southport, Qld, in 1968 and died there in 1975.

Mansfield's younger brother was Sir Alan Mansfield, Chief Justice of Queensland and Governor of the State from 1966-72.

Medical graduate of University of Sydney, MB 1916, MS 1926. Saw active service in France 1917-8 with a machine gun battalion. Worked as a doctor in Sydney, Cairns and Brisbane and, in 1929, went to Moorfields Eye Hospital in London to specialize as an eye surgeon. Practised for a short time in Vienna, and then returned to Brisbane. He had a private practice and appointments to the Mater Hospitals. A modest and reserved man who enjoyed his weekends on his farm at Tambourine Mountain. As a surgeon he was quick, dextrous and decisive.  [MJA 1976 Oct 16;2 (16):621-2.]