Three hundred and fourteen acres of his father's land were laid off to him, in Halifax, Cumberland County, west of Connecticut River, now Windham County, Vt. He was a soldier and an ardent patriot during the Revolution. At the time of enlistment he was a resident of Cambridge, Mass. Serving as first Lieutenant in Capt. John Calef's Co., N.H. troops his name appearing on a return of the company, dated at Great Island, Piscataqua Harbor, November 5, 1775, enlisted June, 1775, length of service six months. Enlisted January 1, 1776, private, John Wood, Capt. Paul D. Sargent, Col. length of service one year. Enlisted February 11, 1777, private. From the History of Windham is the following: "There is enlisted out of Windham on May 8, 1779, Robert Stewart in the Continental Army to serve for three years." In October of this year he participated in the short but decisive battle of Saratoga. He served as ensign in Capt. Benjamin Whittier's Co., Col. Jacob Gale's N.Y. regiment, his name appearing upon the pay roll of this company, dated, Exeter, November 4, 1778, which joined the Continental Army on Rhode Island. He served his country faithfully and was one of the earliest pensioners
(Severance, B. Frank. Genealogy and biography of the descendants of Walter Stewart of Scotland and of John Stewart who came to America in 1718 and settled in Londonderry, N.H. Greenfield, Mass. : T. Morey & Son, 1905, pg. 73-74)