Mexborough succeeded his father in the earldom in 1778. However, as this was an Irish peerage it did not entitle him to a seat in the British House of Lords (although it did entitle him to a seat in the Irish House of Lords). In 1808 he was elected to the House of Commons for Lincoln, a seat he retained until 1812.
Lord Mexborough married Elizabeth, daughter of Henry Stephenson, in 1782.
4th United Kingdom Parliament.