Wain was born and grew up in Stoke-on-Trent, Staffordshire, the son of a dentist, Arnold Wain, and his wife Annie, née Turner. He had an older sister and a younger brother, Noel. After attending Newcastle under Lyme High School, he entered St. John's College, Oxford, gaining a first in his BA in 1946 and MA in 1950. He was a Fereday Fellow of St John's between 1946 and 1949. On 4 July 1947, Wain married Marianne Uffenheimer (b. 1923 or 1924), but they divorced in 1956. Wain then married Eirian Mary James (1920–1988), deputy director of the recorded sound department of the British Council, on 1 January 1960. They had three sons and lived mainly in Wolvercote, Oxford. Wain married his third wife, Patricia Adams (born 1942 or 1943), an art teacher, in 1989. Wain taught at the University of Reading during the late 1940s and early 1950s, and in 1963 spent a term as professor of rhetoric at Gresham College, London. He was the first fellow in creative arts at Brasenose College, Oxford (1971–1972), and was appointed a supernumerary fellow in 1973. In that same year, he was elected to the five-year post of Professor of Poetry at the University of Oxford: some of his lectures are collected in his book Professing Poetry. Wain was appointed a CBE in 1984. He was made an honorary fellow of his old college, St John's, Oxford, in 1985. He died inOxford on 24 May 1994.