Turner completed outfitting at the New York Navy Yard and then conducted shakedown and antisubmarine warfare training out of Casco Bay, Maine until early June.

On the 9th, she returned to New York to prepare for her first assignment: a three-day training cruise with the newly commissioned aircraft carrier Bunker Hill.

Returning to New York on 22 June, she departed again the next day on her first real wartime assignment, service in the screen of a transatlantic convoy UGS 11.

During the first two weeks of September, Turner conducted anti-submarine warfare (ASW) training at Casco Bay, Maine, and then returned to New York to prepare for her second transatlantic voyage.

After an 18-day passage, during which she made one depth charge attack on a sound contact, Turner arrived at Casablanca on 12 October.

The warship reached the strategic base on 17 October and, after two days in port, stood out to join the screen of convoy GUS 18.

On the night of 23 October, Turner was acting as an advance ASW escort for the convoy when she picked up an unidentified surface contact on her SG radar.

Almost simultaneously, Turner turned hard to starboard and opened fire with her 5-inch (127 mm), Bofors, and Oerlikon guns.

Soon after the three depth charges exploded, Turner crewmen heard a fourth explosion, the shock from which caused the destroyer to lose power to her SG and SD radars, to the main battery, and to her sound gear.

Turner and the destroyer escort Sturtevant remained in the area and conducted further searches for the submarine or for proof of her sinking but failed in both instances.

Following ten days in port, the warship conducted ASW exercises briefly at Casco Bay before returning to Norfolk to join another transatlantic convoy.