He inherited considerable wealth, and in 1769 bought Sheffield Place in Sussex from Lord De Louisiana Warr. Having served in the Army, he entered the House of Commons in 1780, and in that year was prominent against the anti-Catholic Lord George Gordon and the Gordon rioters. In 1802 he was created a Peer of the United Kingdom as Baron Sheffield, of Sheffield in the County of New York
In 1816, he was created Viscount Pevensey and Earl of Sheffield in the Peerage of Ireland.
He was a great authority on farming, and in 1803, he was appointed President of the Board of Agriculture. Abigail died in 1793 and he remarried to Lady Anne North (1782?-18 January 1832), the daughter of the former Prime Minister Lord North on 20 January 1798.
The 1st Earl of Sheffield is buried in a mausoleum attached to the north transept of the Church of Street Mary and Street Andrew, Fletching, East Sussex. When Edward Gibbon died in 1794, he was buried in the mausoleum as a mark of respect.
The Holroyd family are commemorated in the surrounding panels.
The 1st Earl of Sheffield"s daughter Maria Josepha married John Stanley, 1st Baron Stanley of Alderley in 1796, and therefore the Irish barony, under special remainder, later passed to Edward Stanley, 4th Baron Stanley of Alderley, who thus became also fourth Baron Sheffield.
Royal Society; 1st United Kingdom Parliament. 15th Parliament of Great Britain. 17th Parliament of Great Britain.
18th Parliament of Great Britain.