Sampson, William (1764–1836), United Irishman and lawyer, was born 27 January 1764 in Derry city, third of three sons of the Rev. Arthur Sampson, anglican clergyman of that city, and Mary Spaight Sampson, of the Dobbs family of Co. Antrim. Sampson's sister Margaret married the Rev. John Dubourdieu, author of statistical surveys of Counties Antrim and Down. His brother the Rev. George Vaughan Sampson (qv) published a statistical survey of Derry. From the age of four he was raised by his father's eccentric maiden aunt and developed athletic prowess, especially in boating. Commissioned in the Irish Volunteers in 1782, he studied at TCD, but did not graduate. After studying law at Lincoln's Inn, he was admitted to the Irish bar in 1792, settled in Belfast, and was active in the north-east circuit with John Philpot Curran (qv). In 1790 he married Grace Clarke of Belfast, whose parents, the Rev. John Clarke and Catherine Anne Clarke (née Coates), were early members of the Belfast Society for Promoting Knowledge, and whose sister Elizabeth married Dr James MacDonnell (qv). Their first son died in 1792; their second son, John Philpot Curran (1795–1820), died a prominent attorney in New Orleans; their daughter Catherine Anne (b. 1796) married in 1825 William Tone (qv), son of Theobald Wolfe Tone (qv), who clerked in Sampson's law office in New York and who died in 1828 when their daughter Grace was a baby.
Sampson's legal and literary careers were intertwined in Ireland and in America. A lawyer, a political activist who helped draft the Belfast resolutions for parliamentary reform in 1796, an expert stenographer who reported trials that stirred public interest, a radical pamphleteer, and a satirist of political events, he wrote almost forty books and pamphlets. He served as defence counsel with John Philpot Curran in the trials of many Defenders and United Irishmen in the North, but he claimed that he never took the United Irish oath except in court, to make the point that reform, not treason, was the objective. He published anonymous reports of the trials of the proprietors of the Belfast United Irish newspaper, the Northern Star, for libel (1794), and of the Rev. William Jackson (qv) for high treason (1795). He was lead counsel at the celebrated trial of William Orr (qv) for administering the United Irish oath (1797). Some of his contributions to the Northern Star were published separately, including Advice to the rich (1796) and his popular political satires, Review of the lion of Old England (1794), co-authored with Thomas Russell (qv), and A faithful report of the trial of Hurdy Gurdy (1794). His verse also appeared in United Irish publications. In 1797–8 he contributed letters signed ‘Fortesque’ to the Press, the United Irish newspaper in Dublin.
His activities with a secret committee collecting proofs of the crimes being committed by the military in Ireland, and his defence of his client John Stockdale (qv), printer of the Press, led to his being charged with high treason on 12 February 1798, shortly after the arrest of members of the United Irish executive. After his offer to surrender – if promised a fair trial – was ignored, in April he escaped to England, where he was arrested and returned to Dublin, imprisoned but never tried, and eventually exiled to Portugal in early 1799. He was arrested there by order of the English minister in March 1799 on suspicion of having written a pamphlet against the union. In May 1799 he was sent to France, where he lived in Bordeaux under close French surveillance (though he seems also to have been under continuous English surveillance while in exile). From the winter of 1800 until May 1805 he was in Paris (where his wife and children joined him in 1802), followed by a year in Hamburg, where he obtained a passport to England. He was arrested on his arrival in London and was sent to New York on 12 May 1806.
On 4 July 1806 he arrived in poor health in New York city, where he was admitted to the bar (October) and welcomed by fellow United Irish exiles Thomas Addis Emmet (qv) and William James MacNeven (qv). Renowned for his wit and conviviality, he achieved professional and financial success and rose to prominence as lawyer, legal reporter and reformer, and writer. His wife, son, and daughter joined him in 1810. Several of his cases made legal history: in 1809 he defended the city's cordwainers' union against conspiracy charges; in 1813 he successfully argued for the sanctity of the catholic confessional against judicial inquiry and published The catholic question in America; in 1824 he defended the Irish catholic weavers of Greenwich Village against riot charges that stemmed from their violent confrontation with local Orangemen on 12 July; and in 1831 he defended catholic Irish accused of rioting in Philadelphia. His most noteworthy contribution to the American legal system was his challenge to the common law as unacceptable in a democratic republic and his advocacy of its replacement by codification, most notably in his Discourse on the common law (1823). In 1825 he and his wife, to be near their daughter, moved to Washington, where he continued to practise law.
Sampson's Memoirs (1807; 2nd ed. 1817) recount his life up to 1807. He edited American editions of John Philpot Curran's life by his son William Henry Curran (qv) in 1820, and in 1833 History of the civil wars in Ireland by William Cooke Taylor (qv), in both of which he included valuable additional historical and personal information. Sampson returned to New York in 1830 and died there on 28 December 1836. His library was sold at Philadelphia in 1837. An engraving of Sampson is in the NLI; his portrait is prefixed to the later American editions of his Memoirs (1817, 1832). Sampson and Clarke family papers are in the PRONI; additional Sampson materials are in the F. J. Bigger (qv) collection at Belfast Public Library; and Sampson letters (1806–31) are in the Library of Congress.