[citation needed] He was again assigned to duty in the Philippines, serving from 1908 to 1910, when he was transferred to Fort William Henry Harrison, Montana, where he remained until 1911.

Gregory was then assigned to the Office of the Quartermaster General in Washington, D.C., where he served from 1928 to 1933, and he received a master's of business administration degree from Harvard University in 1929.

As Quartermaster General during World War II, he oversaw the development, procurement and distribution of billions of dollars worth of equipment and supplies.

In addition, he had responsibility for over 900,000 civilian personnel employed by contractors to produce supplies, equipment, ammunition and vehicles for the war effort.

[citation needed] General Gregory died at Walter Reed Army Hospital in Washington, D.C., on January 26, 1961, and was buried in Section 2, Lot E 134–2 at Arlington National Cemetery.