William Hall Gage was born to Thomas Gage and his wife Benedicta Maria Theresa Hall on 6 January 1717/18 and christened 31 January 1717/18 at Westminster St James, Middlesex.
From 1744 Gage served five terms as Member of Parliament representing the Seaford borough of Sussex.
As the eldest son, he succeeded his father to the title Viscount Gage on 21 December 1754.
[3] Since he had no heirs male, he was again ennobled as Baron Gage of Highmeadow in the Peerage of Great Britain in 1790, but this time with special remainder to the heirs male of his brothers.
Thomas's son Sir William Hall Gage served as Admiral of the Fleet in 1862.