The daughter of Henry and Mary Williams Middleton of Middleton Place, Sarah "Sally" Middleton had eleven siblings, including Arthur Middleton, a member of the Continental Congress and signer of the Declaration of Independence, and Thomas Middleton of The Oaks, prominent in the Revolutionary War and in politics. Her marriage to Charles Cotesworth Pinckney on September 28, 1773 solidified the union between two of the most prominent families of Charleston. Together they had four children: Charles Cotesworth Pinckney, Jr., Maria Henrietta, Harriett, and Eliza Lucas. Having long suffered from tuberculosis, Sarah died at a young age leaving Charles Cotesworth a widower with three young daughters. Five days after her death her father Henry Middleton, added a codicil to his will : "It is therefore my Desire that my son-in-law Charles Cotesworth Pinckney Esquire do receive every Benefit, and Advantage, to which his wife would have been entitled had she survived me."