In 1943 she was transferred back to the Army and converted into a hospital ship, USAHS Chateau Thierry, in which role she was to serve for the remainder of the war.

Chateau Thierry played a part in the assumption by the United States of responsibilities in the western Atlantic in the period before entrance into World War II as she carried Army and civilian personnel and cargo from Brooklyn, New York, to ports in Greenland, Iceland, and Nova Scotia, between 13 September 1941 and 2 January 1942.

[2] On 15 July 1941 Chateau Thierry was transferred from Army to Navy and continued operations between Brooklyn and outposts in Greenland, Iceland, and Nova Scotia during September 1941 and 2 January 1942.

[3] With the entry of the United States into the war, she sailed from Brooklyn 15 January 1942 carrying some of the first American troops to cross to Northern Ireland.

Two more voyages with soldiers from New York to Argentia, Newfoundland, followed, and on 19 May, she got underway for Charleston, South Carolina, to embark Army and civilian passengers.

She remained off Sicily for 2 days, firing to aid in turning back the heavy German air attacks, and taking on board Italian prisoners of war.