Power's movie career was interrupted in 1943 by military service. He reported to the U.S. Marines for training in late 1942, but was sent back, at the request of 20th Century-Fox, to complete one more film, Crash Dive, a patriotic war movie released in 1943. He was credited in the movie as Tyrone Power, U.S.M.C.R., and the movie served as a recruiting film.
In August 1942, Power enlisted in the Marine Corps. He attended boot camp at Marine Corps Recruit Depot San Diego, then Officer's Candidate School at Marine Corps Base Quantico, where he was commissioned as a Second Lieutenant on June 2, 1943. As he had already logged 180 solo hours as a pilot before enlisting, he was able to do a short, intense flight training program at Naval Air Station Corpus Christi, Texas. The pass earned him his wings and a promotion to First Lieutenant.
In July 1944, Power was assigned to Marine Aerial Refueler Transport Squadron 352 as an R5C transport co-pilot at Marine Corps Air Station Cherry Point, North Carolina. The squadron moved to Marine Corps Air Station El Toro in California in October 1944. Power was later reassigned to VMGR-353, joining them on Kwajalein Atoll in the Marshall Islands in February 1945. From there, he flew missions carrying cargo in and wounded Marines out during the Battles of Iwo Jima (Feb-Mar 1945) and Okinawa (Apr-Jun 1945).
For his services in the Pacific War, Power was awarded the American Campaign Medal, the Asiatic-Pacific Campaign Medal with two bronze stars, and the World War II Victory Medal.
Power returned to the United States in November 1945 and was released from active duty in January 1946. He was promoted to the rank of Captain in the reserves on May 8, 1951.
In the June 2001 Marine Air Transporter newsletter, Jerry Taylor, a retired Marine Corps flight instructor, recalled training Power as a Marine pilot, saying, "He was an excellent student, never forgot a procedure I showed him or anything I told him." Others who served with him have also commented on how well Power was respected by those with whom he served.
Captain Power, we salute you for your service. R.I.P.