Rupertus began his military career immediately after high school, originally intending to serve as a cutter captain in the United States Revenue Cutter Service the earlier version of the modern Coast Guard.
Rupertus began his military career immediately after graduating high school, serving in the D.C. National Guard from 1907 to 1910. Originally he intended to serve as a cutter captain in the United States Revenue Cutter Service the earlier version of the modern Coast Guard.