DeHaven joined the Army Air Forces in early 1942.
In 1943 he was assigned to the 7th Fighter Squadron of the 49th Fighter Group stationed at Dobodura, New Guinea. DeHaven shot down 10 Japanese aircraft in offensives over Buna, Lae, Markham Valley, Hollandia and Biak islands. During seven days beginning in late October 1944, DeHaven downed four more enemy planes in the Philippines, bringing his total tally to 14.
He received several medals, including the Silver Star with one Oak Leaf Cluster, which was awarded after he saved a fellow pilot whose plane was surrounded by Japanese fighters.
