In the following months she performed plane guard patrol between San Diego and Seattle, Washington with time out for aircraft tending duties at Sitka, Alaska (14–17 June); Dutch Harbor and Kodiak (15–31 July).

After overhaul in the Puget Sound Naval Shipyard she returned to Kodiak 16 October 1941 to resume tending of amphibious patrol planes in Alaskan waters.

She was serving at Kodiak when the Japanese attacked Pearl Harbor and returned to the Puget Sound Naval Shipyard 9 February 1942 for overhaul.

She arrived at San Diego 13 June and spent the following months as plane guard for aircraft carriers training along the California coast.

She then sailed with Rear Admiral Morton L. Deyo's Gunfire and Covering Force, en route via the Marshalls, Marianas and Ulithi for the invasion of Okinawa.

On 28 April she departed Okinawa in the screen of Makassar Strait, bound via Guam to San Pedro Bay, Philippine Islands.

That carrier launched planes 29 June to land bases on Okinawa and Gillis helped escort her back to Guam 3 July 1945.