Clinton joined his father’s regiment at an early age.
On coming of age in 1806 the 4th Duke of Newcastle returned Clinton to Parliament on his interest at Boroughbridge—two years later his brother Henry became his colleague. When present (he went on a secret mission to Sweden in 1807) he gave a silent support to the Portland and Perceval ministries. In 1810 there was some confusion between his and his brother’s votes, but he voted for the address, 23 Jan., against the Scheldt inquiry (if only by pair) and against the discharge of Gale Jones the radical, 16 Apr. The Whigs were rightly doubtful of him that session. He was in the ministerial minority on the Regency, 1 Jan. 1811. In the following year he proceeded to Sicily and thence to Spain. He was listed a Treasury supporter abroad after the general election. While on leave he voted against Catholic relief, 2 Mar. 1813, but returned to Spain a month later, commanding the first division at Castalla. On the recall of Sir John Murray, Lord William Bentinck awarded him the command in chief. In May 1814 the Duke of Newcastle fell foul of Lord Liverpool and the Prince Regent in a bid to obtain Clinton the red ribbon and the government of Gibraltar: they would not be bullied.
