Joseph Brunson Barnwell was born in Florence, South Carolina, on September 13, 1913, son of Robert W. and Malinda McBee Brunson Barnwell. He attended Florence public schools and was graduated with the degree of Bachelor of Science in Civil Engineering from Clemson College, Clemson, South Carolina in 1934. At the same time he graduated from ROTC Infantry Reserve. He was promoted to First Lieutenant in 1937, was commissioned Lieutenant (jg) in the Civil Engineer Corps of the US Naval Reserve in December 1940, and transferred in that rank to the Civil Engineer Corps of the US Navy in November 1941. He subsequently advanced in rank to that of Captain, to date from July 1, 1956.
Six years as a civil engineer in bridge construction and design with the US Public Roads Administration preceded his reporting for active Naval service in April 1941 as Assistant to the Inspector of Naval Material at Pittsburgh, Pennsylvania, in connection with plant expansion. He remained in Pittsburgh after the outbreak of World War II in December of that year, and in June 1942 became Officer in Charge of Civil Works Contracts. Detached from the latter duty in June 1943, he served for eight months as Maintenance Officer, Floating Drydocks, at San Francisco, California, and from April to June 1944 had duty under instruction at Williamsburg, Virginia.
From July 1944 throughout the remaining war period and until January 1946 he was at Tinian, Guam, as Executive Officer of the Naval Construction Regiment, and later as Officer in Charge of the Construction Battalion. Upon his return to the United States, he reported in February 1946 to Davisville, RI, where he had further instruction until May of that year, and in June was transferred to Philadelphia, Pennsylvania, for duty on District and Shipyard Public Works. He remained there until September 1949, then completed the Senior Course, in Amphibious Warfare, at the Marine Corps Schools, Quantico, Virginia, in June 1950.
From July 1950 until December 1952 he had staff duty, first on the Staff of Commander Service Force, Atlantic Fleet, and from February 1951 on the Staff of the Commander in Chief, US Atlantic Fleet. In January 1953 he reported as Public Works Officer at the Naval Air Station, Seattle, Washington, and in August of the same year was sent to the Naval Station, Treasure Island, for similar duty. In September 1955 he became Deputy District Public Works Officer, Fourteenth Naval District, with headquarters at Pearl Harbor, TH. On December 11, 1947, he was ordered detached for duty as Public Works Officer, Naval Station, Key West, Florida.
Captain Barnwell has the American Defense Service Medal; the American Campaign Medal; Asiatic-Pacific Campaign Medal with one operation star; the World War II Victory Medal; and the National Defense Service Medal.
Captain Barnwell is a member of the American Society of Civil Engineers; Society of American Military Engineers; and Tau Beta Pi (Honorary National Engineering Fraternity).