Komura graduated from the Naval Staff College in 1929, and with a promotion to lieutenant commander assumed command of the destroyer Kuretake, followed by the Namikaze two years later. From 1932 to 1934, he was naval attaché to the United Kingdom. After his return to Japan, he served in various staff positions. He was promoted to captain on 15 November 1938.
Komura was captain of the battleship Fusō from December 1942-June 1943 and Musashi from June–December 1943.
Komura was promoted to rear admiral on 1 November 1943. Appointed chief of staff of the First Task Force, Komura took part in the Battle of the Philippine Sea in June 1944. In October 1944, Komura assumed command of the 1st Carrier Division shortly before the Battle of Leyte Gulf.
On 16 November 1944, the light cruiserYahagi was assigned as the flagship of Rear Admiral Komura's new DesRon 2. On 6 April 1945, Komura received orders for Operation Ten-Go, to attack the American invasion force on Okinawa. Yahagi was ordered to accompany battleship Yamato from Tokushima for its final suicide mission against the American fleet.
At 12:20 on 7 April, the Yamato force was attacked by waves of 386 aircraft (180 fighters, 75 dive bombers, 131 torpedo bombers) from Task Force 58.
At 12:46, a torpedo hit Yahagi directly in her engine room, killing the entire engineering room crew and bringing her to a complete stop. Dead in the water, Yahagi was hit by at least six more torpedoes and 12 bombs by succeeding waves of air attacks. Yahagi capsized and sank at 14:05 at 30°47′N128°08′E / 30.783°N 128.133°E / 30.783; 128.133 taking 445 crewmen with her. Komura was among the survivors rescued by the destroyer Yukikaze.
Recalled to Japan in May, Komura was stationed in Tokyo Bay as commanding officer of Yokosuka Naval District until 30 November 1945.
Komura lived on after the war until 1978. He was portrayed by actor Hirotarō Honda in the 2005 Japanese movie Yamato.
Feifer, George (2001). "Operation Heaven Number One". The Battle of Okinawa: The Blood and the Bomb. The Lyons Press. ISBN1-58574-215-5.
Hara, Tameichi (1961). "The Last Sortie". Japanese Destroyer Captain. New York & Toronto: Ballantine Books. ISBN0-345-27894-1. — First-hand account of the battle by the captain of the Japanese cruiser Yahagi.
Yoshida, Mitsuru; Minear, Richard H. (1999). Requiem for Battleship Yamato. Annapolis, Maryland: Naval Institute Press. ISBN1-55750-544-6. A first-hand account of the battle by Yamato's only surviving bridge officer.