Since the air threat never materialized and the submarine menace proved almost as benign, she fired no shots at the enemy but struggled mightily against the inhospitable Aleutian climate.

Ammen arrived at her destination on 2 October and spent the ensuing nine days practicing gunnery, torpedo, and antisubmarine warfare (ASW) techniques.

Steaming by way of Funafuti in the Ellice Islands and Espiritu Santo in the New Hebrides, the warship arrived at Milne Bay, New Guinea, on 18 December.

For the next nine months, Ammen focused her energies on the series of operations that wrested control of the northern coast of New Guinea from the Japanese and isolated their big bases in the Bismarck Archipelago at Rabaul on New Britain and Kavieng on New Ireland.

In addition to providing antisubmarine and antiaircraft protection for the larger ships, she transported casualties from the battle ashore and conducted shore bombardments.

During the first half of March, Ammen busied herself providing gunfire support for the soldiers securing a hold on Los Negros and fighting off air attacks.

After several weeks of upkeep at Milne Bay and training exercises in that vicinity, Ammen put to sea once again on 18 April in company with Rear Admiral Crutchley's cruiser-destroyer force to support the next hop in the leapfrog along the northern coast of New Guinea-the Aitape-Hollandia invasion.

During the assault at Tanamerah Bay, the destroyer provided antisubmarine and antiaircraft protection to gunfire support ships of the force and contributed her share of call fire as well.

After a respite at Manus, Ammen departed Seeadler Harbor in mid-May in company again with Admiral Crutchley's Australian and American cruisers and destroyers.

On 30 June, the warship put to sea in the screen of the bombardment force assigned to the seizure of Noemfoor, an island located between Biak and the Vogelkop.

During the landings on 2 July, Ammen drew no gunfire support missions and so, contented herself with antisubmarine and antiaircraft defense patrols against an enemy notable only for his absence.

Between the conclusion of her part in the Noemfoor occupation and the Sansapor operation late in July, the destroyer carried out harassment missions against bypassed Japanese garrisons on the New Guinea coast from the base at Aitape.

For the first five days of the Leyte undertaking, she continued to provide antiair and antisubmarine coverage to Wasatch and escorted her out to sea during her nightly retirements from San Pedro Bay.

By the time she was detached to join TG 77.3 on the afternoon of 25 October to guard the eastern entrance to Leyte Gulf, the Japanese had shot their bolt.

On the very first day, 1 November, a burning Yokosuka P1Y "Frances" twin-engine bomber struck Ammen 15 feet from the bridge crew taking off a searchlight and two stacks.

Repairs to her battle damage carried out at the Mare Island Navy Yard kept Ammen out of the Lingayen Gulf operation in January 1945, and their completion at the beginning of the second week in February came too late for the destroyer to play a part in the mid-February seizure of Iwo Jima.

The two warships reached Oahu on 15 February, and Ammen performed training and carrier escort missions in the Hawaiian Islands until the middle of the first week in March.

The task force arrived off the assault beaches early in the morning of 1 April-Easter Sunday, April Fool's Day, and L-day for the invasion of Okinawa.

After tracking her first bogey on radar picket duty just after midnight on the 21st, she failed to detect a second plane that flew in low and dropped a bomb fairly close aboard on her starboard quarter.

That afternoon, an enemy raid-part of the fourth of the 10 major air assaults mounted by the Japanese in the effort to thwart the Okinawa invasion-approached Ammen and Bennion, the ship she was supporting on the radar picket station.

Not long before noon on 1 May, Ammen, relieved by Ingraham, headed for Hagushi anchorage to receive on board a fighter director team along with its equipment.

On 13 May, Ammen returned to radar picket duty, relieving Lowry as fighter director on station 16 about 50 miles west northwest of the peninsula on Okinawa known as Zampa Misaki.

Relative peace returned to radar picket station 15 that night, and continued until early on 27 May when the Japanese launched their eighth kikusui attack-the last in which 100 or more planes were involved.

The destroyer participated in two more similarly futile anti-shipping sweeps of the East China Sea during the last days of July and the first week in August.

Steaming by way of Midway, Pearl Harbor, San Diego, and the Panama Canal, the warship arrived in Charleston, South Carolina, two days before Christmas 1945.

After refresher training out of Guantánamo Bay, Cuba, in July and August, Ammen returned to Charleston in September for a modernization overhaul that lasted until the spring of 1952.

En route, she took quite a detour, steaming via Suva in the Fiji Islands to Melbourne, Australia, to participate in the celebration of the 15th anniversary of the Allied victory in the Battle of the Coral Sea.

Ammen arrived back in San Diego on 14 October and, after post-deployment stand down, resumed normal 1st Fleet operations along the California coast.

In a deployment plagued by engineering casualties, Ammen still managed extended service at sea with the fast carriers of TF 77 and on the Taiwan Strait patrol.

Ammen steamed into San Diego on 18 December and remained there exactly 10 weeks completing the usual post-deployment and holiday leave and upkeep period and preparing for regular overhaul.