Edward was born the son of Colonel Nathaniel Barnwell (1705 – 1775) and Mary Gibbes (1722 – 1801). He was a descendent of explorer and diplomat, Dr Henry Woodward, and his grandfather was Indian war hero, Colonel John "Tuscarora Jack" Barnwell. Edward was baptized Jan 1758 at St Helena Parish where he was later elected to the Vestry in 1787. At the start of the Revolutionary War, at age 17, he entered the Militia of South Carolina. He was commissioned as Lieutenant of the Beaufort Artillery and led an expedition to Georgia under the command of Colonel Stephen Bull of Sheldon. March 3, 1779, his company routed the British under the command of his brother, Captain John Barnwell at the Battle of Port Royal, also known as Grays Hill. At the siege of Charleston 1781, he was taken by the British on St James Island, then held prisoner with his brothers, John and Robert, and his father-in-law, Major William Hazzard Wigg aboard the prison ship, Packhorse as hostages for an exchange with Loyalist prisoners. While the ship was sailing north, Edward and thirty-five men overtook the ship and ran it into the ground off the coast of North Carolina. They escaped and by the end of the war, he was promoted to Lieutenant Colonel. In 1783, he married Mary Bower Williamson (1762 – 1789) at St Helena Parish and they had son, Edward. In 1790, he married Mary Hutson Wigg and they had eleven children. Edward and his brother, Senator Robert Gibbes Barnwell built and shared with their sister wives, a tabby mansion known as "The Castle" which stood on a bluff with a view of the Beaufort River. It was in this house, he died April 15, 1808 of gout. His obituary from City Gazette (Charleston, SC), May 2, 1808 stated, "Died, at Beaufort, S.C. on Friday, the 15th inst, Col. Edward Barnwell. He has left a wife and nine children with a numerous train of relatives and friends, to lament his loss. Col Barnwell was friendly and hospitable, charitable and humane; and was a descendant of one of the most ancient families of this place..."