Nathanael was the son of Nathanael Greene (1707–1770), a Quaker farmer and smith, and the great great grandson of John Greene and Samuel Gorton, both of whom were founding settlers of Warwick, Rhode Island. Nathanael was born on Forge Farm at Potowomut in the township of Warwick, Rhode Island, on August 7, 1742 new style. His mother, Mary Motte, was his father's second wife. Though his father's sect discouraged "literary accomplishments," Greene educated himself, with a special study of mathematics and law. The Rev. Ezra Stiles, later president of Yale University, was a strong influence in the young Nathanael's life.
In 1770, Greene moved to Coventry, Rhode Island, to take charge of the family-owned forge (foundry), just prior to his father's death. There, he was the first to urge the establishment of a public school and in the same year he was chosen as a member of the Rhode Island General Assembly, to which he was re-elected in 1771, 1772 and 1775. It is debatable that he was a member of the General Assembly since there is no mention of his participation in his personal papers and because there were several of his contemporaries with the same name from Rhode Island. He sympathized strongly with the "Whig," or Patriot, element among the colonists.
In 1774, he married Catharine Littlefield Greene, also known as "Caty," of Rhode Island.
In August 1774, Greene helped organize a local militia which was chartered as the Kentish Guards that October. His participation in the group was challenged because he had a pronounced limp. At this time he began to acquire many expensive volumes on military tactics and began to teach himself the art of war. In December 1774, he was on a committee appointed by the assembly to revise the militia laws. His zeal in fighting the British and organizing the militia led to his expulsion from the pacifistic Quakers.
On May 8, 1775, he was promoted from private to Major General of the Rhode Island Army of Observation formed in response to the siege of Boston. He was appointed a brigadier of the Continental Army by the Continental Congress on June 22, 1775. Washington assigned Greene the command of the city of Boston after it was evacuated by the British in March 1776. Letters of October 1775 and January 1776 to Samuel Ward, then a delegate from Rhode Island to the Continental Congress, favored a declaration of independence.
On August 9, 1776, he was promoted to be one of the four new major generals and was put in command of the Continental Army troops on Long Island; he chose the place for fortifications, and supervised the construction of redoubts and entrenchments (the site of current day Fort Greene Park) east of Brooklyn Heights. Severe illness prevented him from taking part in the Battle of Long Island. Greene was also a Rhode Island Freemason and bore a masonic jewel, the gift of his Masonic Brother the Marquis de Lafayette, on his person throughout the whole of the revolution.
Greene was prominent among those who advised a retreat from New York City. He also advocated the burning of the city so that the British might not use it. He justified this by asserting that the majority of property was owned by Loyalists. While Washington agreed with this, the proposal was rejected by Congress. He was placed in command of Fort Lee on the New