He joined the ship within two weeks of the completion of the famous Doolittle Raid on Tokyo, 18 April 1942, and just before his carrier and USS Hornet proceeded south toward the Coral Sea to meet an expected Japanese thrust.

On Friday evening, 5 June, Vammen, flying a Douglas SBD Dauntless, with Aviation Machinists' Mate 2nd Class M. W. Clark in the rear seat took off with eight other planes of VS-6, as part of the strike launched to locate and sink what had been erroneously reported as two Japanese carriers.

Subsequently, the SBDs from Enterprise and Hornet found and attacked what they reported to be a "Japanese CL" (light cruiser)— a ship that turned out to be the destroyer Tanikaze.

The next morning, on 6 June, Vammen joined Hornet's planes in attacking the fleeing Japanese heavy cruisers Mogami and Mikuma, a strike that inflicted such severe damage on the latter that it sank later that day.

Following commissioning, Vammen fitted out through mid-August 1944 and later conducted her shakedown out of San Diego, California, into late September before undergoing a post-shakedown availability at her builder's yard.

She then escorted SS Cushman Davis via Funafuti in the Ellice Islands to Espiritu Santo, before she steamed independently to Pearl Harbor, arriving at the Pacific Fleet's main base three days after Christmas 1944.

After patrolling the entrance to Leyte Gulf from 14 to 18 March, Vammen underwent an availability at San Pedro Bay alongside tender Markab (AD-21).

Steaming as part of the screen for Tractor Group "Easy", Vammen reached the Ryukyus on 1 April, the day of the initial landings on Okinawa.

While maneuvering at 15 knots through the congested transport area under poor visibility conditions, the destroyer escort struck a heavy floating object with her bow at 21:00.

Due to the frequent enemy air raids, her crew spent an average of 10 to 12 hours a day at their general quarters stations, but as Commander King noted in his report of the ship's operations, "no undue fatigue or effect on morale or efficiency" resulted.

Offered no opportunity to fire at enemy aircraft during her time off Okinawa, Vammen conducted two "hedgehog" attacks on suspected submarine contacts, neither with observable results.

With the additional problem of a burnt-out drive motor in her surface-search (SL) radar, Vammen departed Okinawa on 8 April, screening LST Group 17 to Leyte.

Arriving at San Pedro Bay on 14 April, she underwent repairs alongside Markab before she was drydocked in ARD-16 to have the damaged starboard propeller replaced.

On 28 May, while anchored at the northern end of the transport area in Hagushi Bay, Vammen picked up Talk-Between-Ships (TBS) reports of incoming aircraft, "bogies", commencing beyond 50 miles (90 km).

The "Tony" suddenly emerged from the low clouds on the escort's starboard quarter, and all of Vammen's 20-mm Oerlikons that could bear opened up, joining the other ships nearby in putting up a fierce barrage of fire.

The "Tony" strafed a tug nearby but, hit in the tail and right wing, burst into flame, lost altitude, and crashed into the water without exploding, clear of any ships.

For the remainder of June, Vammen performed the unglamorous but vital duty of screening transports and of providing local escort services to incoming convoys.

Subsequently visiting Guam and Saipan, Vammen reached Pearl Harbor on 9 November on her way back to the west coast of the United States.

Vammen supported the American occupation forces in their operations from the spring of 1946 into the autumn, touching at ports such as Tsingtao and Shanghai, China; and Kowloon.

The Korean War meant a new lease on life for Vammen; she was reactivated and heavily modified to enable her to perform a specialized anti-submarine warfare (ASW) role.

After proceeding via Pearl Harbor, Midway, and Yokosuka, Vammen arrived at Sasebo, Japan, on 23 August but got underway the next morning for the key port of Wonsan on the eastern coast of North Korea.

Departing Wonsan on 11 November, the destroyer escort reached San Diego on 2 December via the Shimonoseki Straits, Yokosuka, Midway and Pearl Harbor.

The two destroyer escorts remained there from 3 to 8 February 1958, while Vammen transferred 51 sacks of mail destined for Operation Deep Freeze personnel in Antarctica.

She then conducted anti-submarine warfare (ASW), gunnery, and other shipboard training drills off the coast of California between Long Beach and San Diego.

After logistics stops at Midway and Guam for fuel and minor voyage repairs, the destroyer escort reached Subic Bay on 11 March.

From that day until 9 April, Vammen remained on station in the Gulf of Siam, off the coast of South Vietnam, maintaining American presence in that area.

Complying, the two destroyer escorts subsequently screened Valley Forge (LPH-8), Navarro (APA-215), and Point Defiance (LSD-31) while that group took a Marine Corps expeditionary force to Bangkok, Thailand.

The 3rd Battalion, 9th Marines, embarked in the amphibious group were sent to Thailand in an effort to provide the friendly regime with troops to deter any Communist moves across the Mekong River.

At Pearl from 18 June to 11 July, Vammen enjoyed the longest consecutive in-port period since February that year, undergoing much-needed repairs and maintenance.