 O'Connor – in an unusual succession, all three had been either auditor or vice-auditor of the Queen's College Literary and Debating Society in the same era.In 1875, he was a founding member of the Constitutional Society of India, a group promoting political autonomy for India.In 1877, O'Donnell secured a more permanent election to the House of Commons of the United Kingdom as MP for Dungarvan, County Waterford; he held the seat until 1885, when the constituency was abolished.