[1] The predecessor office, lieutenant governor of Upper Canada, was a British colonial officer, appointed by the British government to administer the government of the colony, from 1791 to 1841.
(Prior to 1791, the territory which is now Ontario was part of the old Province of Quebec, which was administered by the colonial governors of the Province of Quebec.)
It was simply an administrative division of the Province of Canada.
Prior to Confederation, the lieutenant governors of Upper Canada were either British colonial administrators or British Army officers.
The first lieutenant governor of Ontario, General Sir Henry William Stisted, was the last British lieutenant governor.