Through the influence of the Prince-Regent, Moira was appointed Governor-General of the Presidency of Fort William, effectively the Governor-General of India, on 11 November 1812. His tenure as Governor-General was a memorable one, overseeing the victory in the Gurkha War (1814–1816); the final conquest of the Marathas in 1818; and the purchase of the island of Singapore in 1819.