"Jimmy Stewart was the first prominent movie actor to join up, though the draft recently reached out for four other notables in in entertainment
and sports: 26-year-old Jackie Coogan, now at Camp Roberts, Calif., and another aspirant for the Air Corps: Sidney Kingsley, 34, author of 'Dead End', 'Men in White' and other plays, assigned to Fort Jay, N.Y.: Ed (Porky) Oliver, $12,000-a-year golf meteor of 1940, at Fort Dix, N.J.; and Hugh Mulcahy, ace Philadelphia Phillies pitcher."
Stewart attained the rank of full colonel by the time the war ended. He would remain in the Air Force Reserves throughout the Cold War and retire as a brigadier general.
Another Jimmy Stewart article can be read here...
More about W.W. II Hollywood can be read here.
