The ship thereafter operated on trans-Pacific service to the Philippines and China, with return voyages via the Panama Canal to New York. Breaks in this schedule took place when she was laid up for a year in the mid-1920s, and later in the decade when she was extensively refitted at the Mare Island Navy Yard, California. She ran aground at Guam on 19 May 1939, but was safely gotten afloat two days later after a considerable effort. In June 1941 USAT U.S. Grant was turned over to the Navy. Placed in commission as USS U.S. Grant (AP-29), she served through World War II, completing her final voyage in November 1945. Returned to the War Department soon afterwards, she was transferred to the U.S. Maritime Commission and laid up in 1946. U.S. Grant was sold for scrapping in February 1948.