He is credited with preventing the mass evacuation of Japanese-Americans from Hawaii, which many have called a shameful episode of racism and jingoism that was felt hardest on the mainland.

Emmons was assigned as commanding officer of Company B, 30th Infantry Regiment at the Presidio of San Francisco and in May 1912 went to Fort Gibbon, Alaska with the 30th.

He became a lieutenant colonel in August and in December was transferred to McCook Field in Dayton, Ohio as assistant chief of the Engineering Division.

Emmons received his second star in March 1939 as part of his appointment as commander of the GHQ Air Force at Langley Field, Virginia, succeeding Col. Frank Andrews, who was not reappointed after four years in the position and was returned to his permanent rank.

This however caused command difficulties since he was now superior in rank to his boss, Major General Henry Arnold, the new Chief of the Army Air Forces.

Emmons was returned by Arnold to Hawaii as commanding general of the Hawaiian Department on December 17, ten days after the attack on Pearl Harbor.

Emmons promised the local Japanese American community in Hawaii that they would be treated fairly so long as they remained loyal to the United States, and he succeeded in blocking efforts to relocate them to the outer islands or mainland in internment camps by pointing out the logistical difficulties.

He became commandant of the Armed Forces Staff College at Norfolk, Virginia, in August 1946 and remained in that position until he retired June 30, 1948.