John Baker Holroyd, first earl of Sheffield, was born in Ireland on December 21, 1735, the second son of lawyer Isaac Holroyd (1707-1778) and Dorothy Baker (d. 1777). In 1760, he joined the army, rising to the rank of captain in the regiment of light dragoons known as the Royal Foresters. Shortly after the death of his older brother Daniel in 1762, he spent three years traveling Europe; in Lausanne, Switzerland, he made a lifelong friend in Edward Gibbon, whose autobiography and posthumous works he later edited and published. In 1768, he succeeded to the estate of his mother's brother, Jones Baker, and a year later purchased Sheffield Park in Sussex, which he developed into a successful farm. He entered politics in 1780, winning a seat in Parliament for Coventry, which he held for four years. He sat again for Bristol from 1790 to 1802. Although he did not hold high office, Sheffield was a frequent speaker in Parliament, being particularly knowledgeable in the areas of agriculture, trade, and finance. He wrote 15 pamphlets expressing his views on a variety of commercial and political topics, including slavery, the Corn Laws, the Poor Laws, and Irish and American foreign relations. He was president of the Board of Agriculture in 1803 and made president of the Board of Trade and appointed to the Privy Council in 1809.
In 1767, Sheffield married Abigail Way. They had two daughters, Louisa and Maria, before Abigail's 1793 death. In 1794, he married Lucy Pelham, daughter of Thomas Pelham, 1st earl Chichester; she died three years later. In 1798, he married Lady Anne North (1764-1832), daughter of Frederick North, 2nd earl Guilford, and they had a daughter Anne and a son George. Holroyd was created 1st baron Sheffield, of Dunamore, County Meath (Ireland) in 1781; 1st baron Sheffield, of Sheffield, Yorks County in 1802; and 1st earl of Sheffield (Ireland) in 1816. He died May 30, 1821.