Jackson, Joseph Devonsher (1783–1857), judge and politician, was born 23 June 1783 in Co. Cork, eldest son of Strettel Jackson, carrier, of Peterborough, Co. Cork, and Mary Jackson (née Cossens). Educated locally by an evangelical protestant minister, he entered TCD in 1800, graduating BA in 1806. Deciding to study law, he entered the King's Inns, Dublin (1803), and the Middle Temple, London (1804). Called to the Irish bar (1806), he began practising on the Munster circuit. During this period his father's business collapsed, but he was able to pay all debts and provide for his family.
Together with Thomas Langlois Lefroy (qv), in 1812 he became an active member of the Kildare Education Society, an organisation for converting catholics to protestantism. Thus his conservative credentials were never in doubt, especially given his membership of Hardinge's Orange Lodge, and his military service (as a private in Westropp's Grenadiers). However, he did not allow his strong religious principles to prejudice his work as a lawyer (or later as a judge), and his impartiality was never questioned. As a speaker he had few equals, although Daniel O'Connell (qv) nicknamed him ‘Leather-lungs’ because of his fondness for long-winded speeches.
He gave evidence to the Irish education inquiry (1824–5), and became KC in 1827. Entering politics, he became MP for Bandon, Co. Cork, in 1835, was reelected in 1837 and 1841, and was chosen for the Dublin University constituency in 1842. An uncompromising supporter of the protestant order in Ireland, he was one of O'Connell's main opponents in the house of commons. Between 1835 and 1840 he voted eight times against municipal reform in Ireland, and was a conscientious attender at debates. Friendly with the tory leader, Robert Peel (qv), he provided much useful, if not objective, advice on Ireland. His legal career continued at home, advanced by his political successes, and in 1835 he was appointed second serjeant, one of the three Irish law serjeants.
In 1841 he became Irish solicitor general despite the opposition of the young Queen Victoria, who had to be persuaded he was not attached to ‘the very violent Orange party’ (Ball, ii, 295). The following year he was raised to the bench as a judge of the court of the common pleas, vacating his seat in parliament and bringing to an end his political career. Serving chiefly on the Munster circuit, he is said to have had a natural sympathy for the prisoners before him.
He resided at Leeson St., Dublin, and Sutton House, Howth. He died 20 December 1857 at Sutton House and was buried in St Fintan's graveyard, Howth. He married (1811) Sarah Lucinda, daughter of Benjamin Clarke of Cullenswood, Dublin; they had no children.