Born 25 February 1865 at Barnstaple, Devonshire, the first child of William Mamford Riley, a civil servant, and Caroline Budd, his wife. He was educated at Eye Grammar School and at the London Hospital. He went to New Zealand in 1892, where he practised in the country for some years and ultimately settled in Dunedin. In 1909 he was appointed lecturer on obstetrics in the Otago Medical School and became afterwards professor of obstetrics and gynaecology in the University of Otago. He retained his country interests throughout his life and owned a large sheep run in central Otago. He served for many years as a member of the City Council, and was for a long period an elder of his church. He married Susan Graham, who survived him with two sons and two daughters. He died on 1 August 1932 and was buried in the Northern cemetery, Dunedin, NZ.