Civil War Union Marine Corps Officer. The son of a Marine Corps officer, he entered the United States Marine Corps as a 2nd Lieutenant during the Mexican War in 1847, and took part in the assault on Chapultepec (receiving a brevet for his gallantry there). During the Civil War he took an active role in securing the coast of South Carolina in the early days of the war by playing a prominent leadership role in the capture of Port Royal, South Carolina on November 7, 1861. During the beginning of General George McClellan’s 1862 Peninsular Campaign, he led a force of 200 Marines that occupied the Norfolk Naval Yard in May 1862. In the 1863 Union attempts to retake Charleston, South Carolina, he served in the engagement at Morris Island, the July 1863 assault on Fort Wagner, and the September 1863 unsuccessful attempt to storm Fort Sumter (garnering a brevet of Major for his conduct while leading a boat attack). Rising to rank of Colonel in 1876, he was appointed the 8th Commandant of the United States Marine Corps, succeeding Brigadier General Jacob Zeilin. During his tenure he improve the post-Civil War training for officers and enlisted men, modernized Corps procedures and standards, and, most importantly, secured an assignments quota of United States Naval Academy graduates to the Corps. He served as Commandant from November 1, 1876 until ill health forced his retirement on January 29, 1891; his 14 years ranks second only to Colonel Archibald Henderson for length of tenure as Marine Corps Commandant. During World War II the attack transport ship USS McCawley (APA-4) was named in honor of Colonel McCawley. It served from its being acquired by the United States Navy from 1940 until it was sunk on June 30, 1943 off the island of New Georgia, by a combination of a Japanese torpedo attack and mistaken American “friendly fire”.