William Eustis was born in Cambridge, Massachusetts, on June 10, 1753, and graduated from Harvard University. Eustis began his national service during the Revolutionary War, relying on a medical education to serve as a surgeon with the Continental Army. Following the war, Eustis began his own practice, and for two more years he served with federal troops as a surgeon during Shays' Rebellion (1786-1787). Entering politics in 1788, Eustis earned a seat in the Massachusetts House of Representatives, serving until 1794. Gaining experience with the national legislature as well, Eustis twice represented Massachusetts in the U.S. House of Representatives (1801-1805 and 1820-1823), serving as chairman of the Committee on Military Affairs during the second stretch. Four years after his initial spell with Congress, Eustis accepted an offer from President James Madison to become U.S. secretary of war, holding that office from 1809 to 1812. In 1814, Eustis became U.S. minister to the Netherlands, and he remained overseas until 1818. He became governor of Massachusetts in 1823 and died while in office, on February 6, 1825.