O’Beirne was the son of a Catholic attorney in Dublin, to whom he was affiliated as a solicitor, and was involved in Liberal politics from the late 1830s.
After acting as legal representative to several Irish railway companies during 1845-6, O’Beirne relocated his business to London, where his first wife died in September 1850.
During the winter of 1864-5, O’Beirne and Lord Fermoy were forced to defend an action for breaching an agreement to establish a joint-stock bank in Vienna, for which the plaintiffs secured damages of £20,000.
O’Beirne made 120 contributions to debate between 1866 and 1868, speaking on landlord-tenant relations, the reform of the Irish Church establishment, and the introduction of commercial enterprises into Ireland.
In June 1867 O’Beirne introduced a bill to amend the Irish Dog Regulation Act, and warmly supported the subsequent Irish land tenure bill, arguing that ‘an almost total absence of all the means of subsistence except from land’ meant that the basis for fair contracts between owners and occupiers was absent in Ireland, and could not therefore ‘be left free … and untrammelled by special legislation’.
O’Beirne was not, however, exclusively concerned with Irish issues, and took a close interest in the development of army ordnance.
Having participated in the effort to have capital sentences on the leaders of the 1867 rising commuted, O’Beirne condemned the subsequent maltreatment of Fenian prisoners in March 1868.
Having been judged to have laboured for three years in parliament ‘with a zeal, ability, and distinction displayed by few of [his] party’, O’Beirne was re-elected for Cashel in November 1868, and spoken of as a lord of the treasury, his experience in commercial and manufacturing affairs being regarded as sufficient qualification for service in any financial department of the administration.
In March 1869 O’Beirne and his partners were granted a concession by Count Bismarck for laying a new Atlantic cable between Germany and the United States.
O’Beirne died at his residence at Bryanston Square, Marylebone, London in 1895.
