He MA (NUI) PhD (Cambridge) MRIA FTCD retired as Professor of Contemporary Irish History at Trinity College Dublin in 2020. He was previously Professor of Government at Dublin City University. He specialises in 20th century Irish and British history and politics. Since 2002, he has been a member of the National Archives Advisory Council. He is also a member of the Royal Irish Academy National Committee for History, the Royal Irish Academy National Committee for the Study of International Relations and of the Katherine Kavanagh Trust. Amongst his works are The Decline of the Union: British government in Ireland, 1891-1920 (1987); Defending Ireland (1999); and (with D. Ó Corráin), The Dead of the Irish Revolution (2020). He is preparing studies of An Island at War: Ireland 1922-23 and Neighbours from Hell: Afghanistan and the Second World War Belligerents, 1933-1947.
In 2013, O'Halpin presented In the Name of the Republic, which was shown on TV3 (Ireland)
O'Halpin, E. (1987). The decline of the Union: British government in Ireland, 1892–1920. Dublin.
O'Halpin, E. (1989). Head of the Civil Service: A study of Sir Warren Fisher. London.
O'Halpin, E. (1999). Defending Ireland: The Irish state and its enemies since 1922. Oxford.
O'Halpin, E. (2002). MI5 and Ireland, 1939–1945: The official history. Dublin.
O'Halpin, E. (2008). Spying on Ireland: British intelligence and Irish neutrality during the Second World War. Oxford.
Kennedy, M., & O'Halpin, E. (2000). Ireland and the Council of Europe: From isolation towards integration. Strasbourg.
Armstrong, R., Ohlmeyer, J., & O'Halpin, E. (Eds.). (2006). Intelligence, statecraft and international power. Dublin.
Crowe, C., Fanning, R., Kennedy, M., Keogh, D., O'Malley, K., & O'Halpin, E. (Eds.). (1998–2016). Documents on Irish foreign policy (Vols. I–X).
Beiner, G., & O'Halpin, E. (2017). Epilogue. In E. F. Biagini & M. E. Daly (Eds.), The Cambridge social history of modern Ireland [in press].
O'Halpin, E. (2017). British cryptanalysis and China, 1937–1945: An underused source for recent Chinese history? Twentieth Century China, 42(2), [in press].
O'Halpin, E. (2016). Rethinking Irish civil military relations in the 21st century. Defence Forces Review, 217–224.
O'Halpin, E. (2016). Ireland: Plus ça change, 1945–2015. In B. de Graaff & J. Nyce (Eds.), Handbook of European intelligence cultures (pp. 183–195). Rowman & Littlefield.
O'Halpin, E. (2016). The fate of indigenous and Soviet Central Asian Jews in Afghanistan, 1933–1951. Holocaust and Genocide Studies, 30(2), 298–327.
O'Halpin, E. (2015). Augustine Birrell 1850–1933. In L. White & J. Quinn (Eds.), 1916 portraits and lives (pp. 48–53). Dublin.
O'Halpin, E. (2015). British intelligence, PIRA, and the early years of the Northern Ireland crisis: Remembering, forgetting and mythologizing. In P. Maddrell (Ed.), The image of the enemy: Intelligence analysis of adversaries since 1945 (pp. 162–191). Washington, DC.
O'Halpin, E. (2015). “I am sure there was confidence in Nero”. In K. Rafter & M. O’Brien (Eds.), The state in transition: Essays in honour of John Horgan (pp. 318–325). Dublin.
O'Halpin, E. (2014). Ireland and World War II. In A. Jackson (Ed.), Oxford handbook of modern Irish history (pp. 719–735). Oxford.
Breathnach, C., & O'Halpin, E. (2014). Scripting blame: Irish coroners' courts and unnamed infant dead, 1916–32. Social History, 39(2), 210–228.
O'Halpin, E. (2013). Problematic killing in the Irish War of Independence: The killing of spies and informers. In J. Kelly & M. Lyons (Eds.), Death and dying in Ireland, Britain and Europe: Historical perspectives (pp. 173–198). Dublin.
Breathnach, C., & O'Halpin, E. (2012). Registered ‘unknown’ infant fatalities in Ireland, 1916–32: Gender and power. Irish Historical Studies, 38(149), 70–88.
O'Halpin, E. (2012). The Military Service Pensions Project and Irish history: A personal perspective. In P. Brennan & C. Crowe (Eds.), Guide to the Military Service (1916–1923) Pensions Collection (pp. 144–165). Dublin.
O'Halpin, E. (2012). Counting terror: Bloody Sunday and “The dead of the Irish Revolution”. In D. Fitzpatrick (Ed.), Terror in Ireland 1916–1923 (pp. 141–157). Dublin.