Parnell was born in Dublin on 3 July 1776, and committed suicide by hanging in London on 8 June 1842 after a prolonged period of ill-health and depression. His father was Sir John Parnell, Chancellor of the Irish Exchequer and a noted writer on Irish government finance and currency. Charles Stewart Parnell, the Irish nationalist leader, was his great-nephew. Parnell was educated at Eton and then at Trinity College, Cambridge, but left without taking a degree. He was elected MP for Maryborough in the Irish parliament in 1797. Like his father, he opposed union with Britain and voted against it. This did not prevent him standing for the United Kingdom parliament in 1802, and he served briefly as MP for Queen's County and then Portarlington, losing his seat in each case thanks to his earlier opposition to the union. He was finally returned unopposed for Queen's County in 1806 and held that seat until 1832, going on to represent Dundee from 1832–41. He became a baronet in 1812, succeeding to the title held by his elder brother.
From The Biographical Dictionary of British Economists in Oxford Reference.