He was created 1st Viscount Weymouth, on 11 December 1682, with a special remainder; if he lacked male heirs among his own descendants, the title would be inherited by his two brothers, James and Henry Frederick. He was created 1st Baron Thynne of Warminster on 11 December 1682. On 13 December 1688, Weymouth carried an invitation to William III, Prince of Orange at Henley-on-Thames, along with Thomas Herbert, 8th Earl of Pembroke, after the flight of King James II in the Glorious Revolution.