Catharine Littlefield was born into a prominent and wealthy family on Block Island, Rhode Island. Her father, John Littlefield, was a successful merchant and landowner. This upbringing provided her with a strong education, social connections, and a familiarity with managing household affairs and finances – skills that would prove invaluable later in life.

At the age of 17, Catharine Littlefield married Nathanael Greene, a man 13 years her senior. Greene, a Quaker from Rhode Island, would soon become a pivotal figure in the burgeoning American Revolution. This marriage propelled Catharine into a world of political discourse and military strategy, shaping her future experiences and perspectives.