Next came special training off Maine, and her return to Norfolk to join the hunter-killer group formed around USS Mission Bay (CVE-59).

Operating with this group south of the Cape Verde Islands on 30 September 1944, Fessenden and two other ships investigated a contact, making a depth charge attack late in the afternoon, sinking U-1062 in 11°36′N 34°44′W / 11.600°N 34.733°W / 11.600; -34.733.

She returned to Guantanamo 12 February 1945 to rejoin the Mission Bay group as it provided air cover for a convoy northeast of Bermuda carrying President F. D. Roosevelt home from the Yalta Conference.

Fessenden served at New London, Connecticut, and Quonset Point, Rhode Island, in May and June 1945, aiding in the training of submariners and aviators.

She cleared Eniwetok 4 January 1946 for San Diego, California, New York City, and Green Cove Springs, Florida, where she was decommissioned and placed in reserve 24 June 1946.

After antisubmarine training out of Key West, Florida, Fessenden returned to her home port, Newport, Rhode Island, 25 September 1952 to begin duty on the radar picket stations of the North Atlantic.

With her division, she sailed from Newport 15 July 1957 for Pearl Harbor, her home port for Pacific early warning radar picket duty from 18 August 1957 until 18 March 1960 when she left the Hawaiians for San Francisco, California.