Fox, Luke (1757–1819), politician and chief justice of the common pleas, was the fifth son of Michael Fox of Tully, Co. Leitrim, and Margaret Fox (née Coane). Educated privately by Dr Armstrong, and at a grammar school in Cavan, he entered TCD on 8 July 1773. Supporting himself in university by giving private tuition, he became a scholar (1777), and graduated BA (1779). Deciding on a career in the law, he entered Lincoln's Inn (18 June 1781) and the King's Inns, and was called to the Irish bar (1784). A member of the Whig Club from 1789, he was respected for his subtle and clever mind, but his fiery temperament and unpredictability counted against him. He was also seen as a little too cunning for his own good, and it was sometimes said that his conduct and character befitted his surname. He married (13 January 1791) Anne Annesley, a niece of Lord Ely (qv); they had two sons and one daughter.
Entering the house of commons through his father-in-law's influence, he was MP for Fethard, Co. Wexford (1793–7). He spoke rarely in parliament and only two of his contributions are recorded: against parliamentary reform (1795) and for an absentee tax (1797). By then he was prospering as a lawyer, becoming a king's counsel in 1795. He voted against catholic emancipation in 1795, possibly because of Ely's instruction. In the general election of 1797 he was returned for the borough of Clonmines, Co. Wexford. However, he clashed with Ely when a legislative union was proposed in 1799 and was forced to vacate his seat, which he did by accepting the escheatorship of Ulster. He soon found a seat at Mullingar, Co. Westmeath, and returned to parliament to support the union. As a reward, he was named justice of the commons pleas on 27 February 1800. On the bench he was a firm believer in the impartiality of the judiciary, and he maintained this position despite some criticism. When in 1816 he attacked Lord Abercorn (qv) for his neglect as a landlord, motions were made to impeach him, but the attempt was stymied in the house of lords. He retired from the bench in 1816 because of ill health.
Fox died 26 August 1819. He owned estates at Trimleston, Co. Dublin, and a house at Harcourt St., Dublin. His eldest son, Michael Charles Fox, married (1818) Katherine, daughter of Charles Kendal Bushe (qv). His widow married again (1831), to Thomas West. Jonah Barrington (qv) described Fox as ‘a barrister of very humble origin, of vulgar manners, and of a coarse, harsh appearance, was indued [sic] with a clear, strong, and acute mind, and was possessed of much cunning . . . His progress was impeded by no political principles; but he kept his own secrets well, and, being a man of no importance, it was perfectly indifferent to everybody what side he took’ (Mitchel, 95).