After shakedown and training exercises out of Bermuda, Keith sailed from Norfolk, Virginia 14 September 1943 on the first of three voyages escorting convoys from East Coast ports to Gibraltar.

Keith continued to operate with the hunter-killer group patrolling the waters of the Atlantic, escorting convoys from "mid-ocean point" to ports in Brazil, Bermuda, Newfoundland, Cuba, and the United States.

On 23 April 1945, the hunter-killer group, operating as a combined force against a large wolfpack of U-boats, spotted a partially submerged submarine but could not locate it after it dived.

Keith and a task group ships headed to the position where the Frederick C. Davis had gone down and launched a depth charge attack that lasted some 12 hours before U-546 was forced to surface.

She remained there patrolling and escorting vessels until sailing for the United States on 10 April 1946 via Pearl Harbor and the Panama Canal arriving at Charleston, South Carolina on 15 May 1946.