He was called to the Irish Bar in 1714,[3] made King's Counsel in 1728,[4] and served as Prime Serjeant in 1742.
[1] In 1745 he was one of the judges who presided at the perjury trial which resulted from the celebrated Annesley Peerage Case.
[5] Unfortunately the proceedings, which lasted from early morning to late in the evening without a single break, were so exhausting that he simply collapsed, leaving his Chief, Thomas Marlay, to continue the trial alone.
He lived at Dawson Street in Dublin and Riddlestown Park in County Limerick, which he inherited from his uncle Edward Blennerhassett, who married the heiress Elizabeth Windall.
[1] It was very rare at the time for a fatal duel among members of the aristocracy to lead to a conviction for murder, and the killing did not damage his reputation or his future career.