Early life and Revolutionary War years
Pinckney was born on October 23, 1750, in Charlestown in the Province of South Carolina. His father, Charles Pinckney, was a prominent colonial official, while his mother, Eliza Lucas, was known for her introduction of indigo culture to the colony. Pinckney was the second of three siblings to survive to adulthood; his older sister, Harriett, later married a wealthy South Carolina planter, while his older brother, Charles Cotesworth Pinckney, became a prominent leader in South Carolina. When Pinckney was 3, his father took the family to Great Britain on colonial business, but the elder Pinckney died in 1758. His mother kept the family in Great Britain, and Pinckney studied at Westminster School, Christ Church, Oxford, and the Middle Temple. Pinckney was admitted to the bar in November 1774 and almost immediately left for South Carolina.
Though he had spent the majority of his life in England, Pinckney sympathized with the Patriot cause in the American Revolutionary War. Along with his brother, Charles, he became a captain in the Continental Army in June 1775. After seeing much action, he became an aide-de-camp to General Horatio Gates, and was captured by the British at the disastrous Battle of Camden in 1780. By that time he had married and had an infant child. He was allowed to recuperate from his wounds at his mother-in-law Rebecca Brewton Motte's plantation outside Charleston. In 1781 he and his family traveled to Philadelphia, where he was released by the British in a prisoner exchange. Pinckney returned to the South and that year fought under the Marquis de Lafayette in Virginia.
After the war, Pinckney focused on his plantations and his legal practice. In 1787, he ran for the position of Governor of South Carolina at the urging of his friend, Edward Rutledge. Pinckney was elected governor with little opposition. He strongly favored ratification of the United States Constitution and presided over the state convention that ratified the Constitution.