William Colfax (July 3, 1756 – September 9, 1838) was an American officer who served as Captain of George Washington's Life Guard beginning on March 18, 1778.

[2] When Colfax was 17 years old, he was commissioned as a lieutenant in the Continental Army leading him to be present at the Battle of Bunker Hill in 1775.

[1] Upon one occasion, when he was in the act of giving the word of command to his men, a bullet struck his uplifted sword, shattering the blade, and glancing, skinned one of his fingers.

On another occasion, also while riding on horseback in an exposed position a bullet was sent through his body, just above the hip and below the bowels, entering in front and coming out behind.

The long buff waistcoat he wore at the time is preserved by his grandchildren, and the hole is apparent, made by the almost fatal shot.

Some Hessian soldiers, who had been taken prisoners, saw the blood streaming from his side and into his boot, and gleefully exclaimed, "Mein Gott!

Washington, seeing the state of his captain, told him, "You are in a deplorable condition; I will give you a furlough that you may go home till you recover."

[2] While the American army was encamped at Valley Forge, Washington issued an order, dated March 17, 1778, directing that "one hundred chosen men are to be annexed to the Guard of the Commander in-Chief, for the purpose of forming a corps, to be instructed in the manoeuvres necessary to be introduced into the Army, and to serve as a model for the execution of them."

Colfax succeeded Caleb Gibbs on January 1, 1781, as captain (by Washington's appointment) of his Life Guard until September 5, 1783, having gone on furlough in July.