Following shakedown off San Diego, California and an availability at the Puget Sound Navy Yard, Rooks steamed to the Hawaiian Islands for amphibious landing rehearsals and shore bombardment exercises.

Arriving at Iwo Jima on D-Day, 19 February 1945, Rooks sent her LSTs on their way to the beach, then assumed duties as a radar picket vessel.

Arriving at Okinawa Jima on Easter Sunday, 1 April 1945, Rooks began 87 consecutive days of shore bombardment during which she fired 18,624 rounds of 5 inch shells.

During this period she went to general quarters for bona fide air alerts 131 times, and on four occasions was the direct target of kamikaze attack.

In addition to shore bombardment, Rooks also occupied antisubmarine and antiaircraft patrol stations, and for a number of nights steamed with the surface covering force for the island operation.

After shooting down a Mitsubishi A6M "Zeke" and an Aichi D3A "Val", she escorted Hyman into the Hagushi anchorage and sent a medical officer and pharmacist's mates aboard to aid the wounded.

She acted as a radar picket, as a "pointing" vessel in guiding the sweepers along their track, and was frequently called upon to furnish accurate navigational positions of the buoys laid to mark the limits of the swept area.

She then returned to Nagasaki and carried Rear Admiral William H. P. Blandy, Commander Destroyers, Pacific Fleet, to inspect the former great Japanese naval base of Sasebo.

She continued to operate in Japanese and Okinawan waters until departing Yokosuka on 26 October for Pearl Harbor and San Francisco, where she arrived on 10 November.

On her return to the United States she served as afloat training ship for the students of the Destroyers, Atlantic Gunnery School, then with the summer, shifted to ASW and convoy exercises in which she was employed for the balance of the year.