Lucius Robert O’Brien was born in London on 2 May 1775, the son of Sir Lucius O’Brien 3rd Bt. His mother was Anne, daughter of Robert French of Monivae, MP for co.Galway. After training as a cadet he sailed on the ‘Woodcot’ on 18 June 1795 and arrived in India on 30 Oct. He was posted to the 2nd BNC in 1796 but was adjutant of the 3rd BNC from 1798 to 1800. When the 5th Regiment was raised he transferred there on 29 May 1800 as Quartermaster. He was a Captain Lieutenant in the 5th on 4 Aug 1801 and was on furlough from 1803 to 1805. On his return he transferred as a Captain to the 8th BNC which was newly raised.
When the expedition to Java was organised he raised the Java Light Cavalry from elements of the BNC and commanded it during the campaign of 1811 - 1815. They also fought in the Nepal War of 1814-15. He was then appointed Commanding Officer of the 8th BLC with the rank of major, from 2 Jan 1815 until 1817. In the 3rd Maharatta War he was in charge of the Guide and Intelligence Department. He was promoted to Lieutenant-Colonel on 26 Feb 1820 and went on furlough from 1822 to April 1825. He was appointed CO of the 4th BLC on 7 Oct 1824. He was awarded the CB on 23 July 1823. Lt-Col O’Brien died of cholera at Sultanpur, Benares, on 10 July 1825. He was married to Julia Humphries in Dublin on 6 Jan 1824 and had a son, William.
