Olcott was active during the American Revolution. He served as Sequestration Commissioner for Tory Property in 1777 and was a member of the Vermont House of Representatives in 1778. He was a Colonel in the Vermont militia, and his regiment took part in the Battles of Bennington and Saratoga. From 1781 to 1788 Olcott was commander of the Vermont militia's Third Brigade with the rank of Brigadier General.