Born near Taghmon, County Wexford, the youngest of a political family, he was educated at St Peter’s College, Wexford, Ring College and University College Dublin where he studied medicine. While at College he joined Sinn Féin and the Volunteers, was in charge of the medical unit in the GPO during Easter Week, 1916, and was subsequently interned in Stafford and Frongoch. Elected Sinn Féin MP for Wexford in 1918, he was interned on Spike Island during the War of Independence, opposed the Treaty and was interned in the Curragh. He was a founder member of Fianna Fáil and served in every Fianna Fáil government from 1932 until his retirement in 1965, as Minister for Agriculture, 1932–47, Minister for Health and Social Welfare, 1947–48 and 1951–54, and Minister for Finance, 1957–65.