When WWII broke out, the upcoming star abandoned his lucrative Hollywood contract to fight the Axis. He enlisted in the Marines, was eventually commissioned as an officer and assigned to the OSS. He served in the Mediterranean Theater supporting resistance fighters throughout the Balkans. Hayden’s assignments chiefly included coastal reconnaissance and running supplies through the German blockades across the Adriatic Sea. On these missions he drew heavily on his considerable civilian experience as a yachtsman and seafarer.

His exploits were ultimately recognized with the presentation of the Silver Star for gallantry in action as well as a personal commendation from no less than Yugoslavia’s Marshal Tito. The Washington Post reported the following quote from one of Hayden’s 1944 rating records: “He is essentially a seaman and has demonstrated great skill in handling small vessels on clandestine missions along the Dalmatian coast. He has great courage and has shown an almost reckless disregard of his own life where duty is involved.”