This Day in History: Hercules Mulligan, Spy

On this day in 1740, a future Revolutionary War hero is born. Hercules Mulligan was once a little-known Patriot, but the Broadway musical Hamilton has reintroduced his name into the public lexicon.

Mulligan was a friend of Alexander Hamilton’s, you see, but was he also a spy for George Washington? And did he save Washington’s life? Yes, maybe.

“Evacuation day” and Washington’s triumphal entry in New York City, Nov. 25th, 1783. There are no known portraits of Hercules Mulligan.

The historical record is challenging. “Good intelligence sources do not stay good intelligence sources by leaving a paper trail,” Richard J. Werther observes in the Journal of the American Revolution. “If Mulligan were even half as good as his legend, there should be precious little documentation with respect to his intelligence activities (as in fact is the case).”

We do know that Mulligan came to America from Ireland when he was about 6 years old, and he eventually became a clothing merchant and tailor in New York. It’s said that he was an early supporter of the Patriot cause and one of the Sons of Liberty.

Alexander Hamilton comes into the picture just a few years before the Revolution. He’d traveled from the West Indies and ended up lodging with Mulligan while attending King’s College in New York.

Some believe that late night talks with Mulligan convinced Hamilton to take the colonists’ side—and that Hamilton, in turn, was the individual who encouraged Mulligan to spy for Washington.

Mulligan was in a good position to do so. Washington’s army had been driven out of New York City in September 1776, but Mulligan was still there. His clothing business provided the perfect excuse for interacting with high-ranking British officers.

Some say that he was good at stroking the egos of the British, lulling them into speaking more freely than they should. Others add that he learned much simply from the deadlines he was given for finishing uniforms.

Did he transmit information through the Culper Spy Ring? Perhaps.

Abraham Woodhull, of that spy ring, wrote an October 1778 letter in which he referenced “a faithfull freind and one of the first Charecters in the City” who would “make it his buisiness and Keep his Eyes upon every movement and assist me in all respects and meet & Consult weekly . . . .”

Was the “faithful friend” Mulligan? Maybe. A May 1780 letter from another member of the spy ring would reference “Mr Mullegan” as a possible source of help.

Two stories are often told of Mulligan. In the first, a British officer visits his shop late one day, trying to obtain a coat. “The late hour awakened curiosity,” Alexander Hamilton’s son John writes. “After some inquiries, the officer vauntingly boasted that, before another day, they would have his rebel general in their hands.”

Naturally, Mulligan rushed to get a message to Washington. “[He] hastened unobserved to the wharf,” Hamilton explains, “and despatched a billet by a negro, giving information of the design.”

On another occasion, the British had learned Washington’s route to meet a French General, and they planned to intercept him. Mulligan learned of the plan because the British had bought provisions for the trip from his brother.

Mulligan was again able to warn Washington to take another route.

Matters took a turn for the worse when Benedict Arnold’s treason was discovered, and he joined the British Army. Arnold likely knew that Washington had a source in the city, and he had Mulligan watched. Mulligan was eventually arrested, but, at least according to legend, used “Irish blarney” to talk his way out of trouble.

Will we ever know the complete story? Probably not. But we can know something else: Many heroes operated, silently and behind-the-scenes, in our American Revolution.

But for them, America might never have gained her freedom.

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Primary Sources:

• Claire Bellerjeau & Tiffany Yecke Brooks, Did an Enslaved Chocolatier Help Hercules Mulligan Foil a Plot to Assassinate George Washington? (Smithsonian Mag., Sept. 16, 2025)

• Johan J. Smertenko, Alexander Hamilton (1932)

• Letter from Brigadier General Charles Scott to George Washington (November 7, 1778) (enclosing an October 31 letter from “Samuel Culper”) (both letters HERE)

• Letter from George Washington to Major General Lafayette (July 22, 1780)

• Letter from John Bolton to George Washington (May 8, 1780)

• Letter from Tobias Lear to Hercules Mulligan (February 6, 1792)

• Michael J. O’Brien, Hercules Mulligan: Confidential Correspondent of George Washington (1937)

• Rev War | Biography: Hercules Mulligan (American Battlefield Trust)

• Richard J. Werther, The Incredible Story of Hercules Mulligan (Journal of the American Revolution; June 22, 2021)

• Stories: The Legend of Hercules Mulligan (CIA; June 30, 2016)