Politician. Son of William Cavendish (1698-1755), 3rd Duke of Devonshire, and Catherine Hoskins (d. 1777). He graduated M.A. from Cavendish College, Cambridge in 1753, and was first elected MP for Weymouth and Melcombe Regis in 1754. He later served for other constituencies. On July 13, 1765, Cavendish was appointed Lord of the Treasury, and he later served as Chancellor of the Exchequer for two periods in 1782 and 1783.

The Dictionary of National Biography describes him as "a througly honourable and upright man, whose speeches were more remarkable for their breadth of view and sound common sense than for any brilliance or originality of thought, and whose taste for literature and country pursuits (especially fox-hunting) was considerably stronger than for an active parliamentary life."1