The historic events of the time sparked his transformation from a privileged family member of Loyalists to a dedicated Patriot.

He paid a high price, facing tragedies including a split with Loyalist members of his family, and illness and an early death from disease contracted during the American Revolutionary War.

[2] Tilghman then became a partner in Francis-Tilghman Company, a mercantile business formed with Tench Francis, Jr., an uncle[2] on his mother's side.

[2] In July 1775, the Second Continental Congress appointed him to one of the commissioners directed to make treaties with Indians along the frontier, seeking to ensure that they would remain neutral in the American Revolutionary War.

[2] In the summer of 1775, Tilghman became a lieutenant in the 3rd Battalion of the Philadelphia volunteer light infantry company commanded by Sharpe Dulaney.

[4][5] During the Battle of Monmouth in 1778 and afterwards, Tilghman interpreted written and verbal communications between Washington, Lafayette, Von Steuben, and commanders of the Continental Army's French allies.

[6]The Siege of Yorktown in October 1781 culminated in a Patriot victory and an honor for Tilghman, whom Washington picked to carry the surrender papers to the Continental Congress in Philadelphia.

[8][9][10][11] On October 29, 1781, the Continental Congress voted Tilghman "a horse properly caparisoned and an elegant sword in testimony of their high opinion of his merit and ability.

[13] Tilghman's own journal entry was terse: In the morning Lord Cornwallis put out a letter requesting 24 hours must be granted to the commissioners to settle terms of capitulation of the posts of York and Gloster.

[16]The National Park Service writes that Tilghman was even sick during his ride from Yorktown to Philadelphia "with chills and fever" and that he left the army in 1783 with failing health.

[20]Of all the numerous acquaintances of your lately deceased son, & amidst all the sorrowings that are mingled on that melancholy occasion, I may venture to assert that (excepting those of his nearest relatives) none could have felt his death with more regret than I did—No one entertained a higher opinion of his worth, or had imbibed sentiments of greater friendship for him than I had done.

[24] He is also the namesake of a Baltimore City recreation center[25] and a Daughters of the American Revolution chapter in Bethesda, Maryland.