After two film roles, Hayden left Hollywood and joined the U.S. Marine Corps as a private, under the name John Hamilton, a nom de guerre he never used otherwise. While at Parris Island, he was recommended for Officer Candidate School. After graduation, he was commissioned a second lieutenant and was transferred to service as an undercover agent with William J. "Wild Bill" Donovan's COI office. He remained there after it became the OSS.
As OSS agent John Hamilton, his World War II service included sailing with supplies from Italy to Yugoslav partisans and parachuting into fascist Croatia. Hayden, who also participated in the Naples–Foggia campaign and established air crew rescue teams in enemy-occupied territory, became a first lieutenant on September 13, 1944, and a captain on February 14, 1945. He received the Silver Star (for gallantry in action in the Balkans and Mediterranean; "Lt. Hamilton displayed great courage in making hazardous sea voyages in enemy-infested waters and reconnaissance through enemy-held areas"), a Bronze Arrowhead device for parachuting behind enemy lines, and a commendation from Yugoslavia's Marshal Tito. He left active duty on December 24, 1945
Born Tadeusz Wladyslaw Konopka to a Polish-American family in the Terryville section of Plymouth in Litchfield County, Connecticut, Knight dropped out of high school to enlist in the United States Army in World War II. He was a member of A Company, 296th Combat Engineer Battalion, earning five battle stars while serving in the European Theatre.
Gentlemen, we salute you and thank you for your service to our country. Rest in Peace.