She engaged the aircraft with her .50-caliber Browning machine guns, was responsible for shooting one down, and contributed with her sister ships to another plane's demise.

On 28 January 1942 Trever was in the Alenuihaha Channel off Maui′s Hana Coast 30 nautical miles (56 km; 35 mi) north of ʻUpolu Point, the northernmost point on the island of Hawaii, escorting a two-ship convoy on a voyage from Kahului, Maui, to Hilo, Hawaii, consisting of the 622-ton United States Army Transport USAT General Royal T. Frank and the small cargo ship Kalae with a barge in tow.

On that evening, 9 August, a Japanese cruiser force conducted a surprise attack on the Allied (US and Australian) fleet, resulting in the Battle of Savo Island.

After escorting a further high-speed convoy to replenish land forces engaged on the Solomons she was deployed to search for survivors of the Battle of Cape Esperance, fought on the night of 12 October 1942.

After completing another resupply mission, on 25 October, Trever had been expecting orders to bombard Japanese positions along Guadalcanal's coast.

However, an intercepted message informed Lieutenant Commander Agnew of Trever that three Japanese destroyers were approaching, apparently to bombard the airstrip at Henderson Field on Guadalcanal.

By following this plan, Zane and Trever, both uncamouflaged, might attract the Japanese into the area and raise a strong possibility of the destruction of all four highly vulnerable American ships.

The American ships used evasive action and returned fire from their 3-inch (76.2 mm) guns as Japanese salvos exploded in the sea nearby.

Returning to escort duties, she accompanied the tank landing ship USS LST-343 from Lungga Roads to the Russell Islands on 20 June 1943.

After nightfall, a Japanese twin-float biplane seaplane came over and dropped bombs on the two ships, sending them to general quarters and provoking return fire from Trever′s 20-millimeter guns.

Later that day, with the objective secured, Rear Admiral Fort disembarked at Renard Sound ending Trever's brief role as flagship.

On 5 July 1943, American forces attacked at Kula Gulf to occupy Rice Anchorage and thus to prevent Japanese reinforcements from reaching [[Munda, Solomon Islands |Munda]] from Vila.

On 5 August 1943, Trever joined the light cruiser USS Honolulu (CL-48), which had lost her bow to a Japanese Type 93 "Long Lance" torpedo during the Battle of Kolombangara, and escorted her from Espiritu Santo to Pearl Harbor.

After a month's overhaul at Mare Island Navy Yard, Trever steamed for Pearl Harbor on 8 October 1943 and touched there briefly before heading for Guadalcanal.

On 11 November 1943, she joined the screen for the transport USS American Legion (AP-35) and escorted her to Empress Augusta Bay off Bougainville Island.

At 16:30, a man making emergency repairs topside was washed overboard, and Trever immediately began a search for the missing sailor.