The entry of the United States into World War I brought the end of the ship's commercial service with wartime service as a fast troop transport.
Navy Great Northern was acquired from her owners on 19 September 1917, by the
United States Shipping Board; converted to a transport at the
Puget Sound Navy Yard; and commissioned as USS
Great Northern (ID-4569) on 1 November 1917. Six officers and men of the civilian crew joined the Navy to serve on board. Embarking nearly 1,400 passengers at
Puget Sound, including 500 "enemy aliens," women and children as well as men,
Great Northern sailed for the
U.S. East Coast on 21 January 1918, reaching
New York City on 9 February via the
Panama Canal and
Charleston, South Carolina. On 7 March, she sailed from the Army's then Hoboken Port of Embarkation, later designated the
New York Port of Embarkation, for
Brest, France, with 1,500 members of the
American Expeditionary Force (AEF).
Great Northern returned to Hoboken on 30 March with wounded veterans. From then until August 1919, she made a total of 18
transatlantic voyages, first carrying troops to the fighting zones and then bringing home the victorious "doughboys".
Great Northern decommissioned at New York on 15 August 1919 and was transferred to the
U.S. Army Transportation Service the same day.
Army Great Northern was transferred to the
Army Transport Service (ATS) on 15 August 1919. USAT
Great Northern was home ported at the New York Port of Embarkation 1919–1920 and then transferred to
Fort Mason in San Francisco for Pacific service and home ported there 1920–1921. In February 1920 the ship transported Y.M.C.A. and Red Cross workers from
Vladivostok to San Francisco and in April transported approximately 3,000 American officers and men of the
American Expeditionary Force, Siberia from Siberia to the Philippines.
Great Northern also took a Congressional party on a long Pacific inspection, touching at
Hong Kong,
Honolulu,
Cavite, and then returning to
San Francisco, California in the summer of 1920. The ship was laid up at San Francisco on 1 November 1920. By this time the Army found both
Great Northern and
Northern Pacific, then laid up in New York, too fast and too expensive to operate in peacetime and was attempting to lease them to private operators.
Great Northern was turned over to the Navy by Executive Order on 29 July 1921.
Navy and rename The ship was reacquired by the Navy from the
War Department 3 August 1921 and commissioned 11 August as
Great Northern (AG-9). On 19 November 1921,
Great Northerns name was changed by Presidential order to
Columbia to honor a name long famous in Navy annals. She remained in
New York Harbor, functioning as a floating command post, through the rest of 1921.
Columbia sailed for the
Caribbean to join the annual
Atlantic Fleet winter exercises on 7 January 1922, reaching
Guantánamo Bay,
Cuba, via Charleston and
Key West, Florida on 18 January. Three days later she joined the
battleships , , and at
Guantanamo Bay.
Columbia sailed north on 24 February, reaching New York on 27 February. That same day, Admiral Jones shifted his flag to , and
Columbia sailed for
Chester, Pennsylvania. She decommissioned there on 4 March 1922 and was transferred to the
U.S. Shipping Board. ==Commercial service 1922–1942==