John Graves Simcoe was born in Cotterstock, England, and was educated at Eton Grammar School and Merton College, Oxford. He obtained a commission as ensign in the 35th Regiment in 1770. At the outbreak of the American Revolution, he became a captain in the 40th Foot, and in October 1777 he obtained command of the Queen's Rangers. Simcoe was an able officer, and under his leadership the Rangers became one of the most effective Loyalist regiments. He was captured in an ambush in 1779 and imprisoned for six months. In 1781 he was promoted to colonel and returned to England (wounded) shortly before the surrender of Yorktown.
Simcoe recovered from his injuries at the home of his godfather, Admiral Samuel Graves. He married Admiral Graves' niece, Elizabeth Posthuma Gwillim, in 1782. Elizabeth, a wealthy heiress, purchased their 5,000 acre estate on the River Wolf in Dunkeswell. Simcoe entered Parliament in 1790 as member for St. Mawe's, Cornwall, and the following year he was appointed Governor of Upper Canada. He arrived at his new post in 1792, choosing Niagara for his capital. He surveyed the land, strengthened the province's military defenses, and attracted a number of Loyalist settlers to the area. Health issues forced Simcoe to leave Upper Canada in 1796. A year later, he accepted the governorship of St. Domingo, but left after five months due to illness. John Simcoe returned to England in 1797 with the rank of Lieutenant General. He was made Commander-in-Chief of India in 1806, but died before he could take his post.