He was the only surviving son of Lewis Watson, 1st Baron Rockingham (1584 – 1653) of Rockingham Castle and his second wife, Eleanor Manners (1629 – 1696), daughter of Sir George Manners, of Haddon Hall, Derbyshire and Grace Pierrepont, daughter of Sir Henry Pierrepont.

[1][2] A Whig in politics, he took his seat in the House of Lords in June 1660.

His claims, as owner of the manor of Little Weldon, to do service as Master of the Buckhounds at the coronation of Charles II, and at that of James II, were not allowed.

[1] He married, on 13 November 1654 at St. Giles's-in-the-Fields, Anne Wentworth (1629 – 1696), daughter of Thomas Wentworth, 1st Earl of Strafford (1593 – 1641) and Arabella Holles (d. 1631), daughter of John Holles, 1st Earl of Clare.

He was succeeded in the Barony by his son, Lewis, later created Earl of Rockingham.