Came to Colrain, Mass. with his father and resided on the old homestead, and was prominent and active in the affairs of the town, both in peace and war, serving as a soldier in the last struggle with the French and Indians, in 1755, 1756, and 1757, under Capt. Israel Williams at Colrain and Charlemont. He was one of the Minute-men who marched on the Lexington Alarm in April, 1775, under Capt. Hugh McClellan; later served as Lieutenant in the militia. He was chosen selectman in 1769, 1779, 1781, 1783, 1784, and 1786. In 1770 he with three others bought land lying in Bernardston Gore "on a river called Green River" and in 1771 was one of the signers of a petition to have the Gore annexed to Colrain. He sold his homestead to William Nelson,and went to live with his son ni the Gore.
An inventory of the Lt. William Stewart, late of Colrain, deceased, taken Nov. 19, 1804:

1 Pr tongs and shovel:       1:50
1 Pr and And Irons 2:50
1 Trammel           1:
Pr of Steelyards           1:
1 Table                2:
3 Pewter Platters Plates Bason 3:50
1 Looking glass 1:50          
4 Reeds                3:
1 Strait bodied coat       7:50
1 Pr of Velvet Breeches 2:
1 Pr Silver Knee Buckles 50
One Jacket           1:
One copper Tea Kettle 1:50
Two Iron Pots       3:
One loom           3:
3 chairs            1:50
One log chain           2:50
                $41:50

Eliz Stewart, Admrx. (her mark)
               Clark Chandler, Appraisers
               Jon Lyons
     

(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. 35-37).

They lived on the homestead until about 1770 when he bought a lot in Bernardston Gore, which was annexed to Colrain 1779. This lot was on the west side of Green River (findagrave.com)