On 18 June 1918, the vessel was commissioned into service at New Orleans as USS "West Haven" (ID-2159) for operation with the Naval Overseas Transportation Service (NOTS), with Lt. William M. Tonken, USNRF, in command. Laden with general Army supplies, "West Haven" departed New Orleans on 3 July and steamed to Norfolk, Virginia, where she joined a convoy sailing for Europe. She arrived at Bordeaux, France, on 12 August 1918 and unloaded her cargo over the ensuing days. Departing Bordeaux on the 21st, "West Haven" arrived at New York on 5 September. After shifting to Philadelphia the same day, the vessel there took on board 5,125 tons of general Army supplies before departing on 17 September and steaming to Norfolk, whence she got underway on 23 September in a convoy bound for France. After discharging her cargo at Brest, "West Haven" departed that French port on 3 November. While the vessel was steaming home, the armistice was signed on 11 November 1918 ending World War I. However, the return of peace did not change the ship's duties, as there remained the postwar task of reconstructing Europe which had been devastated by the war. Following a brief layover in New York, "West Haven" loaded 7,075 tons of general Army cargo at Baltimore and sailed on 5 December, bound for France. The ship made La Pallice on 2 January 1919, discharged her cargo over the ensuing days, picked up a return Army cargo, and sailed for Norfolk on the 26th. En route home, she ran low on fuel and was forced to reduce her speed to three and one-half knots. She finally reached Bermuda on 28 February. After topping up her bunkers, "West Haven" arrived at Norfolk on 4 March to load 673 tons of cargo for her fourth and final voyage for NOTS. Departing 28 March, she arrived at La Pallice on 12 April where she discharged her cargo. Moving on to Brest, "West Haven" loaded 2,306 tons of captured German ordnance, aviation supplies and 375 tons of steel rail ballast for the return journey. Departing for New York on 17 May, "West Haven" made an intermediate stop on 23 May at Ponta Delgada, Azores, probably to refuel, before continuing on to her destination. Some days later, "West Haven" came across the stricken British steamer "Beechleaf". The 10,000 ton cargo carrier had been in transit from Baton Rouge to Ireland with a cargo of fuel oil when her engines and steering gear were disabled by a fire which killed one crewman and severely burned another.