MacLoughlin, Cornelius (1753?–1851), merchant and repealer, was born in Dublin into a family of merchants; no other details of his family background are known. According to W. J. Fitzpatrick he was born in 1761 (Dublin catholic cemeteries, 58); his Freeman's Journal obituary, however, states that he died ‘at the very advanced age of 98 years’, indicating that he was born in 1753. He had set up on his own as a wholesale merchant by 1803, operating out of 13 Usher's Quay.
As a young man he was a member of the Volunteers; the fact that a catholic would join such a body, which asserted the rights of the protestant political nation, was an indication of changing catholic attitudes. At the time of his death he was one of the last surviving ex-Volunteers, and his Freeman obituarist records that this was ‘a chapter in his long life to which he always looked back with particular delight’. MacLoughlin went on to become an United Irishman; the same obituarist claims that he ‘held an important place in their plans and councils’ but ‘escaped with a short term of imprisonment through the influence of some persons who had great weight with the government of the day’. Daniel O'Connell (qv) told W. J. O'Neill Daunt (qv) (also a personal friend of MacLoughlin) that MacLoughlin was responsible for the publication of the Letter to Lord Castlereagh (1799) by Arthur O'Connor (qv), which set out O'Connor's version of the negotiations between the imprisoned United Irish leaders and the government and complained that the administration had not fully honoured their side of the deal. According to O'Connell, MacLoughlin was thrown a manuscript from a window of Kilmainham jail as he was passing it one day. O'Connor, who had been placed in solitary confinement after an earlier draft was found in his cell, asked MacLoughlin to get it published. According to O'Connell, MacLoughlin replied that he would do so if he approved of the contents; after reading the letter, he published it. MacLoughlin subsequently defended his actions when he was brought before a select committee of the Irish house of commons, declaring that he got the pamphlet printed and approved its principles; Lord Castlereagh (qv) called him a brave fellow and declared that no punishment should be inflicted on him. When Daunt expressed surprise at such magnanimity on the part of Castlereagh, O'Connell replied that the chief secretary was capable of admiring pluck, and that since by the time of this confrontation the union was virtually carried, he felt no pressing need to shed further blood. (If O'Connell's story is to be believed, it might also be suggested that Castlereagh wished to avoid the appearance of personal vindictiveness in dealing with O'Connor's accusations against himself.)
As a catholic merchant, MacLoughlin had a keen interest in improving the conditions of his co-religionists. He joined the Catholic Committee on its formation (1804), and on 18 December 1812 signed a petition calling an aggregate meeting to protest against recent actions of the Irish government (four other signatories were ex-United Irishmen). From this time he became closely attached to Daniel O'Connell, who ‘loved him with reciprocal affection, and ever pointed to his aged friend as the type of all that was lofty and unspotted in patriotism’ (Freeman/Tablet obituary); W. J. Fitzpatrick (qv) (who believed O'Connell himself had been an United Irishman) regarded MacLoughlin as the prime example of O'Connell's fondness for surrounding himself with former United Irishmen. He later sat on the board of the Catholic Association, which he supported both financially and morally. When O'Connell was contesting the Clare seat (1829) MacLoughlin donated £100 towards his expenses. When that seat was secured it was MacLoughlin who initiated what came to be known as the O'Connell testimonial, subscribing £500 to the fund, and later becoming one of its seven treasurers. When the testimonial, which had raised £30,000, was turned into an annual tribute, he again acted as treasurer. He also organised and coordinated Catholic Association meetings for O'Connell in Dublin when the latter was out of the city.
Unlike many prominent campaigners for catholic emancipation, MacLoughlin followed O'Connell into the repeal movement. As a result of his involvement in politics he was proposed twice (1832, 1837) to stand for Dublin city in elections if O'Connell withdrew from the race. MacLoughlin was a member of the parliamentary committee of the Loyal National Repeal Association of Ireland; he sided with O'Connell's ‘Old Ireland’ loyalists against the Young Irelanders and helped to organise a petition among Dublin repealers in support of O'Connell's opposition to the queen's colleges. Apart from his political activities he also sat on the board of the Dublin catholic cemetery for many years.
He died 26 May 1851 at his home, 14 Fitzwilliam Place, Dublin. His letters to O'Connell can be found in the O'Connell papers (NLI MS 13,648). MacLoughlin, like other second-rank emancipation campaigners and repeal activists, has been overshadowed by O'Connell, but his career is a striking example of continuous nationalist political activity over more than sixty years.