William Heath was an American farmer, soldier, and political leader from Massachusetts. In 1765 he was elected as a member of the Ancient and Honorable Artillery Company of Massachusetts and was elected as the company's lieutenant in 1768 and as its captain in 1770. In December 1774 the revolutionary government in Massachusetts commissioned him as a brigadier general. He commanded Massachusetts forces during the last stage of the Battle of Lexington and Concord in April 1775. As the siege of Boston began, Heath devoted himself to training the militia involved in the siege. In June of that year, Massachusetts named him a major general in the state troops, and the Continental Congress commissioned him a brigadier general in the newly formed Continental Army.

In January 1777, Washington instructed Heath to attack Fort Independence in New York in support of Washington's actions at Trenton and Princeton, but Heath's attack was botched and his troops were routed. He was censured by Washington and thereafter was never given command of troops in combat. General Heath was placed in charge of the Convention Army of John Burgoyne’s surrendered troops after the Battle of Saratoga. In 1780 he returned to command the Highland Department after Benedict Arnold’s treason. After the war, Heath was a member of the Massachusetts Convention that ratified the United States Constitution in 1788. He served in the Massachusetts Senate from 1791 to 1792, and as a probate court judge. In 1806 he was elected the Lieutenant Governor of Massachusetts, but declined the office.