Arthur Harrold Castelazo was born in San Francisco, California, on April 28, 1906. He attended Tamapais High School, Mill Valley, California, and in 1928 graduated from the University of California at Berkeley, with the degree of Bachelor of Science in Civil Engineering. Prior to entering active Naval Service, he was employed by the Public Works Engineering Corporation, San Francisco, California; the Department of Water Resources, Department of Public Works, Sacramento, California; and the Division of Highways, Bridge Department Sacramento. He was appointed a Lieutenant (junior grade) in the US Naval Reserve on January 13, 1936, and subsequently advanced in rank attaining that of Captain, to date from July 18, 1952, having transferred from the Naval Reserve to the Regular Navy on June 15, 1944.
Ordered into active Naval service, he reported in September 1938 to the Navy Yard, Mare Island, California, where he remained until March 1941. The next month he was assigned to the Bureau of Yards and Docks, Navy Department, Washington, DC, where he served as Assistant to the War Plans Officer and Construction Section Head, in the Advance Base Division. In October 1943 he became Executive Officer in the Advance Base Division, Bureau of Yards and Docks, Chicago, Illinois, and in September 1944 transferred, in a similar capacity, to the Pacific Division, Bureau of Yards and Docks, with headquarters at Pearl Harbor, Territory of Hawaii.
In July 1945 he reported as Executive Officer of the Advance Base Construction Depot, Guam, Marianas Islands, and in November of that year became Officer in Charge of the 146th US Naval Construction Battalion, Okinawa. He remained there until February 1946, and after a period of travel and leave, was assigned in July 1946, as Assistant Public Works Officer at the Puget Sound Naval Shipyard, Bremerton, Washington. During the period January 1949 to July 1950 he was Officer in Charge of the 124th US Naval Construction Battalion Adak, after which he had instruction at the Naval War College, Newport, Rhode Island. In July 1951 he assumed duty as an Instructor in the Manpower Branch, Industrial College of the Armed Forces, Washington, DC.
Assigned in June 1952 to the Office of the Chief of Naval Operations, Navy Department, he was Head of the Bureau of Yards and Docks Technical Sectior Logistic Plans Division, until July 1956 when he joined the staff of Commander Naval Forces, Marianas as Force Civil Engineer. Between September 1958 and July 1951 he was Navy Member, Instaffations Branch, requirements and Capabilities Division, J-4, Joint Chiefs of Staff, Washington, DC. He served as Resident Instructor, Resources Division, Industrial College of the Armed Forces, Washington, D.C., until ordered detached in February 1964 for duty as Public Works Officer at the Portsmouth (New Hampshire) Naval Shipyard.
Captain Castelazo has the Naval Reserve Medal; American Defense Service Medal; American Campaign Medal; Asiatic-Pacific Campaign Medal; World War II Victory Medal; Navy Occupation Service Medal, Asia Clasp; and the National Defense Service Medal.