The badge is bugging me!  It certainly is American and he is wearing US badges of rank on his collar  (2 bars  =  Lt in the Navy).  However there should be a centrepiece, a shield with stars and stripes, to his cap badge.  Google any image of a USN offer for comparison, even back in the day.  Can't find one exactly like it though so unless someone can find the exact same one I shall put it way in the today's minor mystery tray.
MaxD