Participating in many of the Pacific War battles and campaigns as a member of several units, Komachi was officially credited with having destroyed 18 enemy aircraft.

In May 1941 he was assigned to the fighter squadron of the newly built aircraft carrier Shōkaku and in the autumn of the same year took part in naval exercises around Kyushu in preparation for the Attack on Pearl Harbor.

While he managed to hit the enemy fighter, which started to emit smoke, he could not confirm the crash and was therefore not officially credited with the kill.

[5] During the Battle of the Eastern Solomons in late August 1942, Petty Officer Komachi was assigned to cover the strike force that attacked US carriers.

While engaged in a lengthy dogfight near USN carriers, Petty Officer Komachi hit a couple of Wildcats, however, he did not have the time to confirm their crashes.

Komachi survived the dogfight and proceeded to the meeting point where the dive and torpedo bombers would wait for the fighters in order to lead them back to the friendly carriers.

During the CAP, he and his section leader Petty Officer Ōmori attacked the USN strike group led by Lieutenant Commander Gus Widhelm that was approaching IJN carriers.

During the defence of Rabaul, he also helped to develop methods for using Type 3 air-bursting phosphorus bombs against enemy bomber formations, which were dropped from a Zero fighter above them.

[3][1] Komachi participated in the last air engagement of World War II on 18 August 1945, when he attacked two B-32 Dominators on a photo-reconnaissance mission over Tokyo.

[9] In 1992 Komachi attended a symposium at Naval Air Station Pensacola, Florida about the Battle of the Coral Sea, as a guest panelist.