Gower, John Leveson-, first Earl Gower (1694–1754), politician, was born in London on 9 August 1694, the eldest son of John Leveson-Gower, first Baron Gower (1675–1709), and his wife, Lady Katherine Manners (1675–1722). He was educated at Westminster School and, from 1710, at Christ Church, Oxford; he was made DCL of Oxford on 19 August 1732. On 13 March 1712 he married Lady Evelyn Pierrepont (1691–1727), the third daughter of Evelyn Pierrepont, first duke of Kingston. The marriage produced eleven children, the third son being Granville Leveson-Gower, first marquess of Stafford; the eldest daughter, Gertrude (1714–1794), married in April 1737 John Russell, fourth duke of Bedford.

As a young man Gower was sympathetic to Jacobitism but was initially uninterested in politics, preferring to spend his time hunting and at the races. From 1720 he began to cultivate his political interest in Staffordshire. With Newcastle under Lyme in his control, he built up support in Stafford, Cheadle (where he was mayor in 1721), and Lichfield. During this period he suffered a series of personal tragedies. His first wife died on 26 June 1727; on 31 October 1733 he was married to Penelope Atkins, Lady Atkins, née Stonhouse, the widow of Sir Henry Atkins, bt, but she died on 19 August the following year. He married his third wife, Lady Mary Grey, the daughter and coheir of Thomas Tufton, earl of Thanet, and the widow of Anthony Grey, earl of Harold, on 16 May 1736.

In political terms the 1730s saw Gower's emergence as the leader of the tories in the Lords. He served as lord justice in 1740 and, after Walpole's fall, was the one tory to take high office as lord privy seal and a privy councillor (12 May 1742) in the new whig ministry. His alliance with his political opponents, a move of considerable party political importance, was short-lived, however. He resigned in December 1743, only to be reappointed as lord privy seal under the Broadbottom administration in December the following year, a position he held until his death in 1754. He personally assured the king of his loyalty during the Jacobite rising of 1745, and raised one of the fifteen recruited regiments, for which he was created Viscount Trentham and Earl Gower on 8 July 1746. In 1748, 1750, and 1752 he again acted as one of the lords justices.

Gower's proximity to the administration provoked criticism from many who saw his actions as desertion of the tory cause. Samuel Johnson included him in his definition of 'renegado' in his Dictionary (1755), though the reference was removed by the printer. However, despite fierce attacks, the Gower interest, comprising seven constituencies in Staffordshire and Westminster, retained both its Staffordshire and Lichfield seats in the 1747 election. The considerable financial cost of preserving his interest was met in part by income from Gower's estate, some of which was given over to industrial production, and from shares in eight other estates, including those of Bath and Albemarle. Unmoved by tory criticisms, he emerged as a loyal Pelhamite in the late 1740s and early 1750s. In June 1751 he refused to follow the lead of his son Lord Trentham, and son-in-law Bedford, and resign in support of the recently dismissed fourth earl of Sandwich. He again refused to give up office on the death of Pelham in March 1754. He himself died on 25 December 1754 at 6 Upper Brook Street, London. Election and family expenses had eaten away at his fortune and at his death there were outstanding debts of £37,861 and over £36,000 in legacies. He was survived by his wife, who died on 9 February 1785, and his second son from this marriage, Rear-Admiral John Leveson-Gower (1740–1792).