The exact duties of the Military Secretary have varied based on the needs and preferences of each Commandant.
There are no existing manuals or orders that dictate the exact role of the Military Secretary.
The position was created by the 17th Commandant of the Marine Corps, Major General Thomas Holcomb, who appointed Colonel Alexander A. Vandegrift as the first Military Secretary in 1936.
At this time the Assistant Commandant moved to his own office space and created a more defined position.
Prior to this move, the Military Secretary performed duties for the Assistant Commandant as well.