Plunket was made a King's Counsel in 1795, and three years later was elected to the Irish House of Commons as a Member of Parliament for Charlemont. After the Act of Union was passed, Plunket lost his seat, and failed to be elected to Westminster for the University of Dublin in 1802, but he subsequently became Solicitor-General for Ireland in 1803, a post he held for two years before becoming Attorney-General for Ireland, again for two years. He was appointed a member of the Privy Council of Ireland on 6 December 1805. As Solicitor General he was one of the Irish officials singled out for attack in a serious of scurrilous letters published under the name "Juverna". The author was soon discovered to be Robert Johnson, judge of the Court of Common Pleas. Johnson was prosecuted for seditious libel, convicted and forced to resign from the Bench in disgrace. In January 1807, he was returned to British House of Commons as a Whig member for Midhurst, representing the constituency for only three months, although he subsequently returned to the House of Commons in 1812 as the member for Dublin University, a seat which he continued to represent until May 1827. In 1822 he was reappointed to the office of Attorney-General for Ireland because William Saurin was implacably opposed to Catholic Emancipation, which the Crown now accepted was inevitable. Plunket, unlike Saurin, supported Emancipation and was able to work in reasonable harmony with Daniel O'Connell to secure it. In 1827, relinquishing his seat in the House of Commons, he was raised to the Peerage of the United Kingdom as Baron Plunket, of Newton in the County of Cork and was appointed Chief Justice of the Irish Common Pleas. He was an advocate of Catholic Emancipation, and served as Lord Chancellor of Ireland from 1830 to 1841, with a brief interval when the Tories were in power between 1834 and 1835. He was forced into retirement to allow Sir John Campbell to assume office. His tenure as Chancellor was not without controversy: opponents accused him of political partisanship, lengthy absences from work, and nepotism on a scale unusual even in an age when it was understood that office holders took care of their relatives.
Family
Plunket was married to Catherine McCausland, daughter of John McCausland of Strabane and Elizabeth Span, daughter of Reverend William Span of Ballmacove, County Donegal. Their son Thomas became Church of IrelandBishop of Tuam, Killala and Achonry. Thomas's eldest daughter the HonourableKatherine Plunket was the longest-lived Irish person ever. Their other children included sons Patrick and Robert, and a daughter, Louisa. In Dublin, Plunket was a member of Daly's Club. He died in January 1854, aged 89, at his country house, Old Connaught, near Bray, County Wicklow, and was succeeded in the barony by his eldest son, Thomas. He lived in considerable state: Sir Walter Scott, who visited him at Old Connaught, left a glowing tribute to Plunket's charm and hospitality, and the excellence of his food and wine.
