Carter, Thomas (c.1650–1726), lawyer and MP, was the son of William Carter and his wife, Margaret Thorpe, of Dinton, Buckinghamshire, England. His father was a brother of Col. Sir John Carter, MP, and a descendant of Thomas Carter, armiger of Bedfordshire, born in the reign of Edward IV. An attorney at law, Carter held the offices of clerk of the errors in the exchequer chamber and clerk of the rules of the court of king's bench, and was also a magistrate. His family came to Ireland during the Cromwellian period, but continued to maintain connections on both sides of the Irish Sea. He was attainted (1689) by the parliament of James II (qv), but had already fled to Chester with his wife. He was listed as having property worth £200 a year in England.
He returned to Ireland in 1689, served in the army at Derry, and fought under King William (qv) at the Boyne. After the Boyne, he captured ‘several divers useful books and writings belonging to King James and his secretaries’, which they had deposited in Christ Church cathedral for safekeeping. Perhaps in reward for his services during the war, he was appointed gentleman usher of the Black Rod on 5 October 1692, and also that month was granted the patent of the office of second serjeant at arms, which brought with it a salary of £200 per a year. The lord lieutenant, Henry Sidney (qv) (1641–1704), also appointed him agent for the protestant purchasers. He became MP for Fethard, Co. Tipperary (1695–9), and Portarlington, Queen's Co. (1703–13). In November 1699 he visited James Vernon, secretary of state, in London to discuss Irish land-grant matters.
He married first (18 December 1681) Margaret Houghton (d. May 1696) at St Audoen's, Dublin; they had a son Thomas (qv) and two daughters. Carter added further to his influence by marrying at Clontarf (2 August 1702) Isabella, widow of the celebrated Wentworth Dillon (qv), 4th earl of Roscommon, whose extensive estates in Co. Meath thus came into the Carter family. Carter had been her agent and adviser for several years. In 1698 he purchased an estate in Co. Meath from Lord Sidney for £3,735, and in 1702 bought the former estate of Sir Anthony Mulledy – 2,157 acres, also in Co. Meath. The University of Dublin awarded him an honorary Doctor of Laws (LLD) (1709). In 1717 he purchased from Edward Southwell (qv), secretary of state, his office of clerk of the crown and prothonotary in the king's bench court for £4,000. When his son married (1719), Carter procured an act of parliament to sell part of his estate in order to raise £9,000 for portions for his grandchildren. Isabella died September 1721 at their house at Hollybrook, Co. Dublin; he died at his house in Jervis St. and was buried at St Bride's, Dublin, 19 August 1726.