Irwin, James Alexander Hamilton (1876–1954), presbyterian minister and Irish nationalist, was born in Feeny, Co. Londonderry. Educated at Magee College, Derry, and New College, Edinburgh, he took a master's degree in philosophy from the Royal University of Ireland, and was ordained a presbyterian minister (24 November 1903) in Killead, Co. Antrim, where he served the congregation till 1926.
A supporter of Irish independence, he offered to travel to the USA during the war of independence to illustrate that it was not solely the catholic population of Ireland who favoured independence. Arriving in the USA in April 1920, he undertook a publicity tour of the southern states with Éamon de Valera (qv), and also toured Canada. During the war of independence, his house was raided and he was charged with possession of a firearm – a blunderbuss relic of 1798. Sentenced to six months in prison, he was released after two weeks, following demands for his release from presbyterians in Toronto. At the Irish Race Conference in Paris in January 1922 he was elected honorary treasurer of the central committee. Concerned about the effect of his political activities on his congregation, he resigned (19 October 1926) as minister at Killead, to take up posts in Edinburgh (1926–8) and Leith (1928–35) before returning to Ireland in 1935 as minister at Lucan, Co. Dublin, a position he held till his death in 1954. A member of the national executive of Fianna Fáil (1945–54), he was appointed to the commission on vocational organisation (1939–43) by de Valera, and was one of the most assiduous attenders, present on 145 of the commission's 164 days. In 1950 he was awarded an honorary D.Litt. by the NUI.
He married Amy, daughter of Robert John Morrell, Bangor, Co. Down; they had two sons. He died at The Manse, Lucan, 27 July 1954.