president with the consent of Congress if it serves national interest. However, this is extremely rare. For example, the record for the longest tenure in any service is held by General Lewis B. Hershey who enlisted in the Indiana Army National Guard in 1911 at the age of 18. He was called up for federal active duty during World War I, receiving a commission in 1916, and subsequently transferred to the regular army at the end of the war. He served in active duty in the Army until the age of 80 before being involuntarily retired in 1973 after 62 years of continuous service. Admiral Hyman G. Rickover is listed as serving for 63 years in the Navy from 1918 to 1982. However his service reflects a time when attending any military academy was considered active duty service due in part from World War I. In today's military rules and regulations, an officer who initially begins their career through a military academy does not begin their service until upon receiving their commission after graduation, even though they are subject to the Uniform Code of Military Justice while attending the academy. See also List of United States military leaders by rank List of United States Army four-star generals List of United States Marine Corps four-star generals List of United States Navy four-star admirals List of United States Air Force four-star generals List of United States Space Force four-star generals List of United States Coast Guard four-star admirals List of United States Public Health Service Commissioned Corps four-star admirals List of active duty United States three-star officers List of active duty United States Army major generals List of active duty United States Marine Corps major generals List of active duty United States rear admirals List of active duty United States Air Force major generals List of active duty United States Space Force general officers List of current United States National Guard major generals List of active duty United States senior enlisted leaders and advisors Staff (military) Notes References Four-star Four-star officers United S United States four-star officers