Private First Class Hejny was a gunner with Company I, 3rd Battalion, 1st Marines, 1st Marine Division. On 27 March 1953, he was defending his outpost near Sogong-ni, Korea, when he was struck by enemy shrapnel and killed instantly.

Hejny was awarded the Purple Heart, the Combat Action Ribbon, the Korean Service Medal, the United Nations Service Medal, the National Defense Service Medal, the Korean Presidential Unit Citation and the Republic of Korea War Service Medal.