O'Dowd was educated at Gartree High School, University of Leicester, the Open University and the University of Aston. He joined the Leicester City Police in 1961 rising to the rank of Chief Inspector. In 1977 he joined the West Midlands Police as a Superintendent. In 1984, along with John Smith and Wyn Jones, he was one of a trio of young provincial rising stars who were appointed to the rank of deputy assistant commissioner in the Metropolitan Police as part of Commissioner Sir Kenneth Newman's drive for modernisation, becoming head of strategic planning. He was Chief Constable of the Northamptonshire Police from 1986 until 1993. He was High Sheriff of Northamptonshire in 2007.
- The Independent (UK newspaper, 1986 to 2016)
- HMIC Profile
- "Provincial policemen join Yard's top ranks", The Times, 18 August 1984
- ‘O’DOWD, Sir David (Joseph)’, Who's Who 2016, A & C Black, an imprint of Bloomsbury Publishing plc, 2016; online edn, Oxford University Press, 2015 ; online edn, Nov 2015 accessed 15 May 2016