 O'Connor's knowledge of modern European languages had helped him to establish himself as a correspondent on European affairs, and he assisted O'Donnell in developing a similar reputation; he spent a brief period on the staff of the London "Morning Post".In the 1874 general election, he was elected Member of Parliament for Galway, but was unseated by the courts in what appears to have been a politically inspired judgment which used certain unsavoury campaigning tactics in which O'Donnell had indulged as its basis.He was succeeded in the seat by his election agent, Dr Michael Francis Ward, who was himself succeeded in 1880 by T.P.