[1] During the first eight years of his career, Kean was stationed on the Western frontier attached to the Ninth Cavalry,[1] eventually taking part in Ghost Dance War against the Sioux.

[2] From 1909 to 1913, Kean was in charge of the Sanitary Division of the Surgeon General's office[1] and developed a system for stockpiling emergency medical field supplies during his tenure.

[1] With the entry of the United States into World War I, Kean was deployed to France as the chief of the U.S. Ambulance Service with the French Army, for which he would receive the Distinguished Service Medal,[1][3] until June 1918, when he was promoted to brigadier general and made Deputy Chief Surgeon of the American Expeditionary Force until the end of the war.

As Chief of the Department of Military Relief, American Red Cross, a position of great responsibility, by his foresight, marked efficiency, and energy General Kean organized the bas hospitals, which cared for many of our wounded, and administered the United States Ambulance Service for duty with the French Army, greatly assisting our ally.

He rendered services of conspicuous worth to the United States.Following his return from France, Kean held key positions in government commissions even after his retirement from the military in 1924.

[2] Kean was appointed member of the U.S. Commission for the construction of the National Expansion Memorial in by the President Franklin D. Roosevelt in 1934.