- Born 10 June 1842 Killegar, Co Leitrim
- Died 22 February 1914, Dublin
- Educated Radley College, Oxfordshire, Dublin University
- Occupation Valuator Irish Church Commission later Commissioner for Lands
- Debut 28 May 1862 v MCC at Lord's
- Cap Number 66
- Style Hand unknown.
- Teams Dublin University.
Murrough O'Brien was a member of the Inchiquin family, being the nephew of one time Tory MP William Smith O'Brien, who, in a remarkable transformation, became the leader of the abortive Young Ireland Rebellion of 1848. Murrough was, therefore, the second cousin of The Hon D O'Brien (Ireland 1902) and of the Gwynn brothers. He was at Radley under the headship of William Sewell, the College's founder. Sewell also founded St Columba's College, Dublin and Trinity College, Glenalmond in Scotland, and was, at different times, Warden (Headmaster) of all three. O'Brien was not a great cricketer at Radley, evidence suggesting that he preferred rowing. He was a member of the First VIII in both 1859 and 1860.
He showed no outstanding talent for cricket at Dublin University either, having entered in September 1860. He was not a regular member of the First XI. His one and only appearance for Ireland was hardly auspicious .Batting at 9 v MCC at Lord's in May 1862, he was caught off the fast roundarmer George Wooton, a Nottinghamshire professional, for 0. He did not get a second innings as Ireland, set the by no means easy target 100 to win on a typically rough Lord's wicket of the time, managed to win by three wickets, thanks to a fine innings by future MCC Secretary Bob Fitzgerald.
Murrough never played for Ireland again. He appears to have left University without taking a degree, before spending some time in New Zealand. When he returned he married Eleanor Waller, of another leading Anglo-Irish family. They had five children as he settled into rather mundane employment.