David Colvin was born 23 Jan 1941, 3rd son of Major Leslie Hubert Boyd Colvin, MC, and of Edna Mary (née Parrott). He was educated at Lincoln School and Trinity College, University of Oxford (MA). In 1971, he married (Diana) Caroline Carew, younger daughter of Gordon MacPherson Lang Smith and Mildred (née Carew-Gibson), having one son and one daughter.

After a short spell as Assistant Principal, Board of Trade, 1966, Colvin joined the Foreign (later Diplomatic) Service in 1967 and during his diplomatic career served in the following posts: Central Departmentt, Foreign Office, 1967; Second Secretary, Bangkok [Thailand], 1968-71; European Integration Department, Foreign and Commonwealth Office, 1971-75; First Secretary, Paris [France], 1975-77; First Secretary (Press and Information), UK Permanent Representation to the European Community, 1977-82; Assistant Secretary, Cabinet Office, 1982-85; Counsellor and Head of Chancery, Budapest [Hungary], 1985-88; Head, South East Asian Department, FCO, 1988-91; Minister, Rome [Italy], 1992-96; Ambassador to Belgium, 1996-2001.