On 20 February 1944 she departed New York in the screen of two escort carriers for duty with Admiral Jonas H. Ingrain's U.S. 4th Fleet based at Recife, Brazil.

Operating out of Recife and Bahia, Brazil, she helped cover coastal waters from the border of French Guiana down to Rio de Janeiro and across the Atlantic narrows more than halfway to the coast of Africa.

On 22 November 1944, while escorting Navy transport General M. C. Meigs (AP-116) to a mid-way rendezvous in the Atlantic Narrows, she closed alongside cruiser Omaha (CL-4) to pass orders and the two ships collided.

After temporary repairs at Bahia, Brazil, Gustafson proceeded north to the New York Navy Yard, arriving on 21 December 1944.

The Gustafson located a sonar contact in the waters northeast of Cape Cod in the early morning of 7 April, and she attacked the target with hedgehogs, but these failed to produce an explosion.

This sinking credit was included on this list because the Gustafson was part of a task force that was commanded by a U.S. Coast Guard officer.

However, the Foreign Documents Section of the Naval Historical Branch of the U.K. Ministry of Defense revoked this credit in April 1994, surmising that the Gustafson attack was "very probably directed against a nonsub target."

[1] Gustafson trained out of New London, Connecticut, with submarines until 18 May 1945 when she put to sea as a unit of the escort for a convoy bound to Oran, Algeria.

Her base Pearl Harbor, she served as a weather patrol ship north of Hawaii for the remainder of the year, thence via San Diego for return to the Atlantic seaboard.