In May 1942, then Lieutenant Shiga took command of aircraft carrier "Jun'yō's" fighter group, a post he held until December 1942. During this time, Shiga led the carrier's fighters in the battles of Dutch Harbor and the Santa Cruz Islands. In the latter battle, he attacked the US carriers, and , in which the former was later sunk, while "Enterprise" was heavily damaged. He subsequently commanded the aircraft carrier "Hiyō's" fighter group from December 1942 through January 1943 while the carrier was in port in Japan.