As most of the folks in his neighborhood were Loyalists, Morris’s conversion didn’t happen overnight.

His public service began in the provincial assembly. One of the better examples of his discontent with the changing relationship to the Crown came when New York was hosting a large garrison of British troops who were there theoretically to protect the American colonies. The Crown intended to tax New Yorkers to support troops, and when the assembly refused to vote in favor of this measure, the governor requisitioned the money anyway. Morris was not happy with this outcome, and, more important, he was not quiet about it.

In 1774, when the colonies were choosing delegates to send to the Continental Congress, Lewis was not selected as a representative. New Yorkers still wanted to make peace with the Crown, and voters considered him too unlikely to support compromise. But by spring 1775, circumstances had changed dramatically. The Battle of Lexington had taken place, and a strong voice was needed in Philadelphia. He was sent this time. Ironically, he wasn’t a big talker in Congress, but he worked on the ever-important committees to secure munitions for the troops. Ammunition, gunpowder, the never-ending search for saltpetre – these were Morris’ primary concerns.

In June 1776, he took a leave from his Congress duties to command the militia in Westchester, New York, as a brigadier general. New York was the only colony to abstain from voting on July 2. But a week after the vote passed, he helped lead New York in approving the Declaration of Independence, which it did on July 9. When he returned to Congress in September, he signed the document. After the war he served as a judge and as a state senator. He lobbied hard behind Alexander Hamilton to ratify the Constitution. Lewis Morris III died on January 22, 1798, at Morrisania, Westchester (Bronx) New York, United States of America.

He is buried at Morrisania in the Morris family vault located in the churchyard of St. Ann’s Episcopal Church in what is now called the Mott Haven neighborhood.