He has held the chairs of Modern History in University College Cork and Professor of History and Glucksman Professor for Irish Studies and Director of Glucksman Ireland House, at New York University.
He also lived for some years in Ballinasloe, County Galway, where he attended national school.
[1] He graduated in 1962 from University College Dublin with first-class honours in History and Economics.
The following year he moved back to Ireland to become Professor of Modern History at University College Cork, succeeding Oliver MacDonagh.
In 1993, he was elected to the 20th Seanad as an independent member for the National University constituency.