David Barrie was born on 9 November 1953, the son of Alexander Ogilvy Barrie and Patricia Mary Tucker. He was educated at Bryanston School and Brasenose College, University of Oxford (studying Experimental Psychology and Philosophy); in 1978, he married Mary Emily, daughter of Rt Hon. Sir Ralph Gibson, PC, having two daughters.

Barrie joined the Diplomatic Service in 1975, and his diplomatic career included: Central and Southern Africa Department, Foreign and Commonwealth Office, 1975–76; Dublin [Ireland], 1976–80; seconded to Cabinet Office Assessments Staff, 1980–81; North America Department, FCO, 1982–83; Republic of Ireland Department, FCO, 1983-87; transferred to Cabinet Office, 1988; seconded to Japan Festival 1991, as Executive Director, 1989–92; resigned from Cabinet Office, 1992.