Crookshank, Alexander (1736–1813), lawyer and politician, was born 30 June 1736 in Dublin, eldest son of William Crookshank, attorney. Educated at Foyle College, he entered Middle Temple (1762) and was called to the Irish bar (1766), beginning a successful career as a barrister. Appointed seneschal to Donegall Manors, Co. Donegal (May 1773), he also served as a commissioner of bankruptcy (1775–7).
Entering politics, he became MP for Belfast (1776) and was again returned in 1783. In parliament he was an enthusiastic supporter of government, and spoke regularly, though not well. He was rewarded for his loyal support in 1781 when he became a KC. One of the few occasions he opposed the government was over a proposed increase in the number of judicial offices. In 1783 he had reason to alter his opinion on the creation of new offices, as the government looked to appoint three barristers to various judicial positions in an attempt to gain favour. Crookshank was offered one of these positions, which he accepted, thus becoming a fourth justice of the common pleas, taking office on 14 January 1784.
Throughout his tenure Crookshank ably supported government. It was therefore no surprise when he was appointed to sit on the special commission in the aftermath of the 1798 rebellion. Four cases came before the commission, involving five people. All were found guilty; four were executed. Crookshank assisted Lord Carleton (qv) with the trial of Henry Sheares (qv) and John Sheares (qv), and presided over one of the other three state trials. This was to be his last significant involvement in judicial affairs. He retired from the bench (December 1800), and lived out his life on a comfortable pension. He died 10 December 1813 and was buried at Monkstown, near Dublin.
He married (1768) a Miss Kennedy of Londonderry; they had several children. He resided in Dublin at Cuffe St., then at Leinster St., and later at Newtown Park, Blackrock, Co. Dublin.