Moore, George Henry (1810–70), politician, landowner, and horse-trainer, was born 1 March 1810 in Moore Hall, Ballyglass, Co. Mayo, eldest among three sons of George Moore (1770–1840), landlord and historian, and Louisa Moore (née Browne), granddaughter of the 1st earl of Altamont. He was educated at St Mary's catholic preparatory school in Oscott, near Birmingham, before enrolling at Christ's College, Cambridge (1827). As a catholic he could not take a degree and spent most of his time gambling and playing billiards. Sent to London in 1830 to study law, he soon fell heavily into debt from gambling and so was recalled again to attend to the family estate of 12,000 acres. From 1834 to 1839 he spent his whole time travelling abroad, visiting Russia, Syria, and Palestine, where he explored the Dead Sea. In 1840, following the death of his father, he returned to Mayo and took charge of the family estate. Together with his brother Augustus, he established a racing stable and both brothers soon became well known as successful jockeys and breeders of horses. Their horses won the Irish Gold Whip in 1843 and 1845, and the Chester Cup in 1845, gaining them over £10,000 in prize money and bets, much of which was used to settle George's substantial gambling debts. Following the death of Augustus while riding in the 1845 English Grand National, George sold his horses and curbed his gambling. During the Great Famine he chaired two committees to dispense relief aid in Mayo and imported 1,000 tons of flour, distributing it to tenants at half-cost. His estate gradually fell into debt, forcing him during 1854 to sell half his property for £5,900.
Although he lost a March 1846 by-election, he succeeded in being elected MP for Mayo during the 1847 general election. At a Dublin convention of liberal MPs (January 1847) Moore proposed that all Irish MPs should take a pledge to cooperate closely on matters of particular importance for Ireland, but the proposal made no impact. He did not have an opportunity to implement his idea until 1851, when he became chief spokesman in parliament for Irish catholics’ opposition to the Ecclesiastical Titles Act. A close friend of Archbishop John MacHale (qv) and Fr Patrick Lavelle (qv), Moore took the leading role in establishing (August 1851) the Catholic Defence Association to oppose the act. On 28 October 1852, with the support of twenty-six MPs, Moore also established in Dublin the short-lived Friends of Religious Freedom and Equality to call for the disestablishment of the Church of Ireland.
Together with Charles Gavan Duffy (qv), Moore played a key role during 1850–51 in compelling all MPs who supported the Tenant League to take a pledge not to accept government office until the league's demands were met. By attempting to use these two platforms, of religious inequality and the land question, to unite Irish liberal and catholic MPs under one banner, Moore was primarily responsible for formulating the policy of ‘independent opposition’ among Irish MPs during the early 1850s, which subsequently became the backbone of the loosely based independent Irish party of the 1850s, of which he was the most consistent champion. After the 1852 general election, together with Duffy and Frederick Lucas (qv), he played the pivotal role in arousing feelings of popular indignation towards his former close associates, William Keogh (qv) and John Sadleir (qv), after they reneged on their Tenant League pledges by accepting government positions on their re-election. However, his support for the Tenant League had made him unpopular among the Mayo landed elite and Moore lost his seat in the 1852 general election.
After 1852, despite the opposition of Archbishop Paul Cullen (qv) and most catholic bishops, Moore continued to put pressure on MPs to adopt the independent opposition policy by using the influence of the Tenant League, of which he was chairman during 1856. During the late 1850s he also made repeated unsuccessful attempts to persuade William Smith O'Brien (qv) to re-enter Irish politics and lead an independent Irish party. In the 1857 general election Moore was re-elected for Mayo, but was unseated on the grounds of undue clerical influence being used against his tory rival. Consequently, the independent opposition policy was effectively taken over by Daniel O'Donoghue (qv), whose 1857 campaign Moore had supported. At the 1859 general election Moore and other ‘independents’ supported the tory government of Lord Derby (qv) to show their disgust with the Palmerstonian liberals – a development which allowed the tories to win a majority of Irish parliamentary seats.
Although he had been opposed to the Young Irelanders during the 1840s, during the early to mid 1860s Moore began expressing support for the idea of a more ‘nationalist’ orientated party to be established in Ireland – an action on his part that has led most historians to view him as having flirted with Fenianism. Indeed, according to John Devoy (qv), Moore was asked to join the IRB by Jeremiah O'Donovan Rossa (qv) during 1864 and was apparently willing. James Stephens (qv), however, did not allow Moore into the organisation because he considered him too conservative. Although it was nominally pledged to support his old independent opposition policy, Moore refused to back the National Association of Ireland (established 29 December 1864) because of his personal feelings of animosity towards Cullen (who virtually controlled the association), and, as a result, he became politically marginalised.
After a short time serving as high sheriff of Co. Mayo, with the encouragement of Archbishop MacHale, Moore decided to run for Mayo in the 1868 general election on a ticket of tenant right and amnesty for Fenian prisoners. A talented and lively speaker, on election he became the most enthusiastic champion of the amnesty cause in parliament, endearing him to a new, young IRB leadership. As a result, throughout 1869 he began conferring regularly with some IRB leaders. In common with John O'Connor Power (qv) and moderate IRB leaders, Moore apparently desired some form of alliance between the Fenians and MPs, with a view to forming a new public movement. As he was still committed to an essentially catholic–whig political agenda, however, it is improbable that Moore ever became a member of the IRB or seriously worked with it on any basis other than promoting the amnesty agitation. He died suddenly of apoplexy on 19 April 1870 while on his way home from London, intending to solve a dispute among his tenants organised by local Ribbonmen.
He married (1851) Mary, daughter of Maurice Blake, a landlord with property in Co. Mayo and Co. Galway. They had five children, including the writer George Augustus Moore (qv) and the soldier and politician Maurice Moore (qv).