The story of Lee Marvin and Bob 'Captain Kangaroo' Keeshan fighting together in the battle for Iwo Jima is an urban legend. Lee Marvin did serve in the Marines in World War II and was wounded in action, but on Saipan, not Iwo Jima. Bob Keeshan enlisted in the Marines in June, 1945, too late to take part in any combat. Source:
www.snopes2.com/military/keeshan.htm.