 Demant became Vicar of St John the Divine, Richmond, in 1933 and nine years later he became a canon of St Paul's Cathedral.He served as canon chancellor of the cathedral from 1942 to 1948 and as canon treasurer from 1948 to 1949.He was a canon of Christ Church, Oxford, and Regius Professor of Moral and Pastoral Theology at the University of Oxford from 1949 to 1971.