Cannon was commissioned on 26 September 1943 and reported to the United States Atlantic Fleet.

On 30 November 1943, Cannon cleared Philadelphia for Trinidad, where she arrived on 5 December to begin a year of duty escorting convoys from that oil rich island to Recife and Rio de Janeiro, Brazil.

During this time, she made one voyage from Brazil to Gibraltar, guarding convoys whose tankers carried the fuel essential to the operations in the Mediterranean.

Cannon's protection of the Allied fuel supply through the sea lanes of the Caribbean and the Atlantic Narrows ended on 4 December 1944, when she arrived at Natal, Brazil to begin training a Brazilian crew in the operation of the ship.

Cannon was decommissioned and transferred to Brazil on 19 December 1944 at Natal.