Perrin, Louis (1782–1864), judge, was born 15 February 1782 probably in Waterford city, son of Jean-Baptiste Perrin (d. c.1820?), peripatetic émigré French teacher and writer. His Irish mother was named Daly. Between 1750 and 1814 his father turned out at least nine French grammars and other didactic works on French pronunciation and idiom, published in London, Dublin, and Naples, which sold well. The large family nevertheless got by with difficulty till coming into wealth c.1790, when Perrin's paternal uncle died in the French East Indies, leaving a fortune of some £30,000 to his brother. Perrin studied first in the Armagh diocesan school in the early 1790s. He matriculated into TCD (7 November 1796), took a classical scholarship (1799), and graduated BA (1801). His politics were liberal from adolescence. In October 1803 he braved a hostile court to embrace Robert Emmet (qv) in the dock at the close of his friend's patriotic speech and apologia. Entering the Middle Temple, London (1804), he kept his terms industriously, there and in the King's Inns, Dublin. If his principles remained liberal, his personality was bookish and unromantic. He had the foresight to master mercantile law, a specialisation little known at the Irish bar but soon to be much in demand.
Called to the Irish bar in January 1806, he joined the north-east circuit, following in the footsteps of Robert Holmes (qv), his patron in the legal world and brother-in-law to Emmet. Sooner than most, he got the recognition of his fellow-barristers. Holmes put him in the way of a steady turnover of cases and his opinion or assistance was sought out in excise prosecutions, principally for the defence. In 1811 Daniel O'Connell (qv) delegated to Perrin the burden of the defence of Watty Cox (qv), under crown prosecution for libel. In November that year Perrin was one of the team of barristers under O'Connell defending members of the Catholic Board prosecuted for violation of the convention act of 1793. Respected by O'Connell as one of the small group of liberal protestant lawyers who resisted the temptations of office, Perrin also made a useful professional ally in Charles Kendal Bushe (qv), solicitor general, who led the prosecution in the latter case. Though he supported the campaign for catholic emancipation in the 1820s, he took little part in electoral politics. In late 1827 he was made KC. On 7 February 1832 he was raised to third serjeant.
On 2 May 1831, shortly before the general election, he announced his intention of contesting the constituency of Dublin city as a reform candidate in partnership with the former mayor, Robert Harty (1779–1832). The importance of reform to the restricted electorate was given added impetus by viceregal threats to corporation sinecures held by anti-reformers and by the lavish entertainment of voters by the so-called ‘Perrin’ election committee, and both Perrin and Harty were returned. In early August 1831 a packed commons committee heard the petition of tory freemen and freeholders against the result and found against the reform organisation, unseating both candidates.
Though in sympathy with the larger part of the O'Connellite political agenda, Perrin shied away from taking the repeal pledge in late 1832. He also pained O'Connell by taking an establishment line late that year when Francis Blackburne (qv), attorney general, attempted to repress the publication of comment critical of the police. The consequent strain on his political relationship with O'Connell meant that he was not backed again in the whig nationalist interest for Dublin city. But he overcame deeply rooted tory opposition in Co. Monaghan in December 1832, reputedly at enormous personal expense, to top the poll as a whig candidate. He and O'Connell, who acknowledged ‘so many good and excellent and amiable points’ about Perrin (O'Connell, Corr., iv, 450), put the dispute behind them in the commons between 1833 and 1835, uniting in pursuit of Irish reform. Perrin, O'Connell, and Andrew Lynch (MP for Galway city (1832–41)) together drafted the bill that led to the intoxicating liquors act of 1833, though Perrin was more interested in the effect on temperance of early closing hours, and O'Connell in curbing magisterial power. On 20 July 1833 Perrin was commissioned to chair a commons inquiry into the state of the Irish municipal corporations. After his tussle with tory stalwarts in Dublin corporation in 1831, this represented a coup for the Irish whig interest. The ensuing report, published 31 July 1835, was one of the crucial documents in the dismantling of Irish ascendancy control of local administration. Though Perrin's rather conservative Irish municipal reform bill of July–August 1835 was stalled in the house of lords after passing through the commons (it eventually took five years for Irish municipal reform to enter the statute book), it heralded the assumption of local power by Irish catholic nationalists.
In late 1834 Perrin refused to take the office of solicitor general if it meant working as subordinate to Blackburne. Elected to the borough of Cashel in January 1835, he was made prime serjeant the following month. Quietly sitting out the stir when he was passed over for a judicial vacancy soon afterwards, he was appointed attorney general 29 April 1835 and gazetted privy councillor, under the whig administration of Lord Melbourne (qv), though no longer O'Connell's first preference. On 31 August 1835 he was appointed to king's bench. Predictably regarded as a liberal partisan by the Irish tory establishment, Perrin was acclaimed by O'Connellites for thorough, unimpassioned attention to detail while showing no favour to the crown side in criminal proceedings. He was noted for the care with which he monitored prosecution in the case of prisoners without counsel. Liberal and conservative alike stifled laughter at his frequent grunts of displeasure, although he demanded stony silence of others in session. During the later 1830s he was persistently in the minority among the twelve judges in arguing at appeal the broader criterion of value in determining £10 freeholdings at registry, a matter with the profoundest electoral consequences. He was among those presiding at the trials of Daniel O'Connell in 1844 and the Young Irelanders in 1848. Ailing by the later 1850s, he resigned from the bench in February 1860, retiring to a villa at Knockdromin near Rush, Co. Dublin. He attended the magisterial bench at petty sessions off and on. He died 7 December 1864 at home in Rush and is buried in the local protestant cemetery.
He married (April 1815) Hester Connor, daughter of the Rev. Abraham Augustus Stewart, chaplain to the Royal Hibernian School in Dublin. They had seven sons.