Stewart began his military career as captain of a Pennsylvania infantry company at the beginning of the American Revolutionary War.

He was a younger son of David and Isabella Stewart of Letterkenny, County Donegal, and in 1772 was sent to join the trading house of Conyngham and Nesbitt in Philadelphia.

[4] One Continental Army private recalled that the ladies of Philadelphia called the good-looking Stewart the "Irish Beauty".

Another observer described him as, "of fair, florid complexion, vivacious, intelligent and well-educated, and, it was said, was the handsomest man in the American army".

Belatedly detecting Howe's column, Washington deployed the divisions of John Sullivan, Lord Stirling, and Adam Stephen to halt the attempted envelopment.

[10] After his brigade endured a three or four-mile double-time march in 45 minutes,[8] Weedon arranged his troops on a reverse slope behind a fence.

As his men came under heavy fire, Monckton asked Hessian Captain Johann von Ewald to ride and get help.

He noted that his men started fighting 1.5 miles (2.4 km) from Germantown and penetrated the British lines as far as the Market House.

[16] After Sir Henry Clinton evacuated Philadelphia and marched toward New York, George Washington moved his army northeast from Valley Forge, Pennsylvania.

[20] As the 1st Guards Battalion came abreast of the woods, the Americans riddled their flank and dropped British Colonel Henry Trelawney and 40 guardsmen.

But the holding actions gave Washington time to deploy Lord Stirling's division athwart Clinton's advance.

He wrote his friend Anthony Wayne, perhaps with tongue in cheek, that the ladies, "have really got the art of throwing themselves into the most wanton and amorous postures", when he was around.

[4] When elements of the Connecticut Line mutinied in 1780 at Morristown, New Jersey, the "dependable" Pennsylvania regiment surrounded them and restored order.

Ignoring orders from their officers, soldiers had assembled under the direction of their sergeants, armed themselves, and had begun to march south toward Philadelphia.

The soldiers had a number of grievances that were viewed as legitimate, and at Trenton, New Jersey, troops negotiated with representatives of Congress and won important concessions, including a new bounty.

After being reinforced to 900 men by the addition of one light infantry and two Pennsylvania battalions, the Americans walked into a British ambush.

[27] In October 1781, Stewart participated in the siege of Yorktown as commander of the 1st Pennsylvania Battalion in General Wayne's brigade of Von Steuben's division.

[29] By the winter of 1782–1783, with the war all but won, Stewart remained in Philadelphia while much of the Continental Army camped at Newburgh, New York.

As officers and soldiers at Newburgh realized that they needed to get Congress to give them their back pay before the army was disbanded, the situation there began to develop into a crisis.

[30] Although Washington was not unsympathetic to his officers' position, he was apprehensive of the consequences of a large-scale mutiny, and notified Congress that he would do all he could to stop the army from rebelling.

[31] According to Rufus King, a majority of American officers expected that after the army was disbanded, they would be considerably worse off as civilians.

[32] At the officers' meeting Washington appealed to his audience not to carry out "any measures which, viewed in the calm light of reason, will lessen the dignity and sully the glory you have hitherto maintained."

[32] Armstrong tried to revive the plot in April but gave it up when someone revealed the plan to Washington, and Gates quietly dropped out of the conspiracy.

[32] According to historian Robert K. Wright Jr., the "wretch" to whom Armstrong referred was either Colonel John Brooks or Walter Stewart.

He settled in Philadelphia across the street from George and Martha Washington and became a successful businessman and major general of the state militia.

[4] Stewart died on June 16, 1796, in that year's deadly yellow fever epidemic and was interred in the burial ground of Old St. Paul's Episcopal Church in Philadelphia.

[4] On April 11, 1781, prior to the British surrender at Yorktown, Stewart was married to Deborah McClenachan, the 17-year-old eldest daughter of a Philadelphia businessman.

[4] Stewart's father-in-law, Blair McClenachan, was known as a founder of the First City Troop, and had bought the house known as Cliveden from Benjamin Chew in September 1779.