Strong and Hawley were both elected to the Massachusetts Provincial Congress in 1774. When the American Revolutionary War broke out in 1775, Strong was unable to serve in the military because of his damaged sight, but he was otherwise active in the Patriot cause. He served on the Northampton Committee of Safety and in other local offices, but refused service in the Continental Congress. He was a delegate to the 1779 Massachusetts Constitutional Convention, and was elected to the committee that drafted the state constitution, ratified in 1780. He then served on the first governor's council and in the state senate from 1780 to 1789.