In March 1867, he was appointed Secretary of State for the Colonies and served until December 1868. He also served as Governor of Madras from 1875 to 1880. As Governor, he handled the relief measures for the victims of the Great Famine of 1876-78. Buckingham also served as Lord of the Treasury, Keeper of the Privy Seal of the Prince of Wales, Deputy Warden of the Stannaries, Deputy Lieutenant of Buckinghamshire, Chairman of the London and North-Western Railway, member of the Imperial Privy Council, Lord President of the Council and chairman of the committees in the House of Lords. He died on 26 March 1889 at the age of 65.