Chatham was the eldest son of William Pitt, 1st Earl of Chatham. He was two and a half years older than his famous brother William Pitt the Younger, the future prime minister. After serving as a junior officer in the American War of Independence, he succeeded his father as Earl of Chatham in 1778. Politically he was a close supporter of his brother during the following decade, leading to his appointment as First Lord of the Admiralty in 1788. Despite overseeing the Royal Navy's victory at the Glorious First of June in 1794, he faced criticism for his handling of the Admiralty and was demoted to the comparatively unimportant post of Lord Privy Seal. Although he continued to serve in William's cabinet, the relationship between the two brothers never fully recovered after this point.