On June 13, 1940 at 20 years of age, Frank joined the Black Horse Troop which was a part of the Illinois National Guard and the last of the US Cavalry. In November 1940, President Roosevelt called up the National Guard and federalized them, making them a part of the United States Army. In September 1942 he entered the Signal Corps Officers Candidate School at Fort Monmouth, New Jersey and became a Second Lieutenant. Over the next 2 years he served stateside and in 1944 his battalion was sent to Okinawa. In 1945 he was transferred to Korea. In 1946 he deployed back to the States where he subsequently left duty and continued to serve in the Army reserves until his retirement in 1968.