Jim Dowd grew up in Lewisham, London, with an Irish father and German mother. He was educated at the Dalmain Infant and Junior Schools in Forest Hill; the Sedgehill Comprehensive School, Catford, and the London Nautical School, Lambeth. He began his career in telephone engineering as an apprentice in 1967 with the General Post Office (GPO). Following his apprenticeship, he became a manager in 1972 at a Heron petrol station for a year before joining Plessey as a telecommunications engineer in 1973, where he remained until his election to the House of Commons.