Desmond FitzGerald was born and raised in London. He was Minister for External Affairs at the time of his son's birth. FitzGerald senior, whose father had emigrated as a labourer, from Skeheenarinky in County Tipperary, had joined the Irish Volunteers in 1914 and fought during the 1916 Easter Rising. FitzGerald senior had been active in Sinn Féin during the Irish War of Independence, and had been one of the founders of Cumann na nGaedheal. The party was formed to support the Anglo-Irish Treaty of 1921, which created the Irish Free State.