John Lysaght, 2nd Baron Lisle of Mountnorth was a member of the English aristocracy living in what is now the Republic of Ireland. Born in 1729 to the first Baron Lisle, and Catherine, daughter of Joseph Deane, by Margaret Boyle. Lysaght was educated at Trinity College, Dublin. He was selected to the Whig parliaments as MP for Castlemartyr in 1753. He was appointed High Sheriff for County Cork in 1757. After the accession of George III in 1760 to the English and Irish thrones, Lysaght was elected as a 'knight of the shire' MP for County Cork for three years in 1765.