McQuaid was born in 1920 in Dungannon, Co. Tyrone, with one elder brother, and a sister. A Roman Catholic, he married a Protestant, and due to the atmosphere at the time in Northern Ireland they decided to move to Dublin in 1948, as Jim's elder brother Paddy had done a year earlier. Jim set up a greengrocery, with a small bakery, in the small district of Ballygall, between Glasnevin and Finglas in the northwestern Dublin suburbs. Jim and Madge McQuaid continued to live in Dublin, and had seven sons and three daughters.
