Isaac Butt (1813-1879), Irish lawyer and Nationalist leader, was born at Glenfin, Donegal, in 1813, his father being the Episcopalian rector of Stranorlar. Having won high honours at Trinity, Dublin, he was appointed professor of political economy in 1836. In 1838 he was called to the bar, and not only soon obtained a good practice, but became known as a politician on the Protestant Conservative side, and an opponent of O'Connell. In 1844 he was made a Q.C. He figured in nearly all the important Irish law cases for many years, and was engaged in the defence of Smith O'Brien in 1848, and of the Fenians between 1865 and 1869. In 1852 he was returned to parliament by Youghal as a Liberal-Conservative, and retained this seat till 1865; but his views gradually became more liberal, and he drifted away from his earlier opinions. His career in parliament was marred by his irregular habits, which resulted in pecuniary embarrassment, and between 1865 and 1870 he returned again to his work at the law courts. The result, however, of the disestablishment of the Irish Church was to drive Butt and other Irish Protestants into union with the Nationalists, who had always repudiated the English connexion; and on 19th May 1870, at a large meeting in Dublin, Butt inaugurated the Home Rule movement in a speech demanding an Irish parliament for local affairs.
On this platform he was elected in 1871 for Limerick, and found himself at the head of an Irish Home Rule party of fifty-seven members. But it was an ill-assorted union, and Butt soon found that he had little or no control over his more aggressive followers. He had no liking for violent methods or for "obstruction" in parliament; and his leadership gradually became a nullity. His false position undoubtedly assisted in breaking down his health, and he died in Dublin on the 5th of May 1879.