She served in the Atlantic Ocean and provided destroyer escort protection against submarine and air attack for Navy vessels and convoys.

She was named after Charles Hazeltine Hammann who was awarded the Medal of Honor, when, as a pilot of a seaplane 21 August 1918, off the coast of Italy, he dived down and landed next to a downed fellow pilot, brought him aboard, and although his plane was not designed for the double load, brought him to safety amid constant danger of attack by Austrian planes.

Between 28 March 1944 and 29 November 1944 the busy ship made no less than six more voyages successfully convoying to and from Europe, stopping at ports in Northern Ireland.

Starting 4 January the ship changed her convoy destination to Liverpool and made four more voyages protecting the vital flow of supplies for the end of the European war.

As the Pacific war was then over, the destroyer escort took on passengers at Pearl Harbor for California, and after discharging them sailed through the Canal again to Charleston, South Carolina, arriving 25 September.