In 1805 he was Chancellor of the Duchy of Lancaster under his intimate friend William Pitt; in the latter year he was sent on a special and important mission to the emperors of Austria and Russia and the king of Prussia. In 1809 he was honoured when he was made Viscount Sandon, of Sandon in the County of Stafford, and Earl of Harrowby, in the County of Lincoln. From November 1809 to June 1812 he served as Minister without portfolio in the cabinet of Spencer Perceval.