Peterson moved to Galveston, Texas, 6 October 1943 to continue her outfitting, then sailed by way of Algiers, Louisiana to Bermuda for shakedown.
She reported to Charleston, South Carolina, for a brief post-shakedown upkeep 22 November, and six days later was en route to New York City, arriving the last day of the month.

Her first voyage between New York and Casablanca, French Morocco, commenced 2 December when Peterson sailed for Norfolk, Virginia to join the main body of a North Africa bound convoy.
She returned to New York 18 January 1944.

Peterson then shifted her activity to Northern Europe, making ten voyages to British and French ports.
On the first of these voyages, Peterson with the other escorts of Division 22 steamed from New York 1 March to screen a fast oiler convoy to Derry, Northern Ireland.
On this voyage a submarine sank Leopold (DE-319).

Peterson arrived with the convoy at Derry and returned to New York 28 March where she was joined by USS Gandy.
Departing New York 15 April with an Ireland bound convoy, Peterson was detached the following day to escort two merchant ships, which had collided, back to New York.
En route to rejoin the convoy later on the same day, Peterson joined Gandy and USS Joyce in rescuing survivors of the torpedoed Pan Pennsylvania and destroying the attacker.
At 13:45 Joyce reported a hot sound contact and the last survivors scrambled on board Peterson just as Joyce dropped a pattern of depth charges.
The submarine shot to the surface at 14:00.
Gandy opened fire on the U-boat which returned fire until rammed with a glancing blow by Gandy two minutes later.
Peterson commenced firing at 14:04 to lay open the conning tower, and as she passed alongside the submarine, fired two shallow-set depth charges at close range from her starboard “K” guns.
At 1409 the submarine surrendered and the crew commenced abandoning the sinking boat.
Joyce picked up the crew and U-550 slid beneath the waves at 14:30.
The three escorts rejoined the convoy and steamed safely to Lisahally, Northern Ireland, returning to New York 12 May 1944.

The sunken German U-boat was found on 23 July 2012 in deep water about 70 nautical miles (130 km; 81 mi) south of Nantucket, Massachusetts.

Peterson made three more convoy voyages to Derry and return.
She then made successive voyages from New York to Plymouth, England (6 October–5 November 1944); from New York to Cherbourg, France and Plymouth, England (23 November – 24 December); from New York to Liverpool, England (10 January–9 February 1945); from New York to Le Havre, France and Southampton, England (27 February – 29 March); and from Boston to Greenock, Scotland and Liverpool, England, returning to New York 16 April.

After an overhaul to fit her for extended duty in the Pacific, Peterson departed New York 4 June 1945 with the rest of Escort Division 22 for exercises at Culebra Island, and at Guantanamo Bay, Cuba.
She transited the Panama Canal 23 June, called at San Diego for voyage repairs, and arrived Pearl Harbor 16 July.
With the end of the war, she reported to Commander Amphibious Group 8 and Commander Transport Squadron 18 for duty.

Peterson departed Pearl Harbor the last day of August 1945 with an LST convoy.
Calling at Saipan en route, the convoy arrived off Wakayama, Japan, 27 September and Peterson assumed patrol in the Inland Sea until 29 October.
On that day she set course for the United States, calling at Pearl Harbor, and arriving San Diego 17 November.
She shifted to San Pedro the following day.
She got underway for the east coast, transiting the Panama Canal 6 December.
Three days later off the coast of Florida, a PBM–3D (Mariner) landed close aboard to ask assistance.
Peterson towed the disabled plane to Ponce de Leon Inlet where a crash boat from New Smyrna took over the tow.
She then continued up the coast to Charleston, South Carolina, arriving 10 December 1945.

Peterson sailed for Jacksonville, Florida, 14 January 1946, arriving the following day to commence her inactivation.
She was placed out of commission in reserve at Green Cove Springs, Florid
Peterson moved to Galveston, Texas, 6 October 1943 to continue her outfitting, then sailed by way of Algiers, Louisiana to Bermuda for shakedown. She reported to Charleston, South Carolina, for a brief post-shakedown upkeep 22 November, and six days later was en route to New York City, arriving the last day of the month.
Her first voyage between New York and Casablanca, French Morocco, commenced 2 December when Peterson sailed for Norfolk, Virginia to join the main body of a North Africa bound convoy. She returned to New York 18 January 1944.
Peterson then shifted her activity to Northern Europe, making ten voyages to British and French ports. On the first of these voyages, Peterson with the other escorts of Division 22 steamed from New York 1 March to screen a fast oiler convoy to Derry, Northern Ireland. On this voyage a submarine sank Leopold (DE-319).
Peterson arrived with the convoy at Derry and returned to New York 28 March where she was joined by USS Gandy. Departing New York 15 April with an Ireland bound convoy, Peterson was detached the following day to escort two merchant ships, which had collided, back to New York. En route to rejoin the convoy later on the same day, Peterson joined Gandy and USS Joyce in rescuing survivors of the torpedoed Pan Pennsylvania and destroying the attacker. At 13:45 Joyce reported a hot sound contact and the last survivors scrambled on board Peterson just as Joyce dropped a pattern of depth charges. The submarine shot to the surface at 14:00. Gandy opened fire on the U-boat which returned fire until rammed with a glancing blow by Gandy two minutes later. Peterson commenced firing at 14:04 to lay open the conning tower, and as she passed alongside the submarine, fired two shallow-set depth charges at close range from her starboard “K” guns. At 1409 the submarine surrendered and the crew commenced abandoning the sinking boat. Joyce picked up the crew and U-550 slid beneath the waves at 14:30. The three escorts rejoined the convoy and steamed safely to Lisahally, Northern Ireland, returning to New York 12 May 1944.
The sunken German U-boat was found on 23 July 2012 in deep water about 70 nautical miles (130 km; 81 mi) south of Nantucket, Massachusetts.
Peterson made three more convoy voyages to Derry and return. She then made successive voyages from New York to Plymouth, England (6 October–5 November 1944); from New York to Cherbourg, France and Plymouth, England (23 November – 24 December); from New York to Liverpool, England (10 January–9 February 1945); from New York to Le Havre, France and Southampton, England (27 February – 29 March); and from Boston to Greenock, Scotland and Liverpool, England, returning to New York 16 April.
After an overhaul to fit her for extended duty in the Pacific, Peterson departed New York 4 June 1945 with the rest of Escort Division 22 for exercises at Culebra Island, and at Guantanamo Bay, Cuba. She transited the Panama Canal 23 June, called at San Diego for voyage repairs, and arrived Pearl Harbor 16 July. With the end of the war, she reported to Commander Amphibious Group 8 and Commander Transport Squadron 18 for duty.
Peterson departed Pearl Harbor the last day of August 1945 with an LST convoy. Calling at Saipan en route, the convoy arrived off Wakayama, Japan, 27 September and Peterson assumed patrol in the Inland Sea until 29 October. On that day she set course for the United States, calling at Pearl Harbor, and arriving San Diego 17 November. She shifted to San Pedro the following day. She got underway for the east coast, transiting the Panama Canal 6 December. Three days later off the coast of Florida, a PBM–3D (Mariner) landed close aboard to ask assistance. Peterson towed the disabled plane to Ponce de Leon Inlet where a crash boat from New Smyrna took over the tow. She then continued up the coast to Charleston, South Carolina, arriving 10 December 1945.
Peterson sailed for Jacksonville, Florida, 14 January 1946, arriving the following day to commence her inactivation. She was placed out of commission in reserve at Green Cove Springs, Florid
USS Peterson (DE-152)