The 28th Marine Regiment sailed as part of the 5th Marine Division under Major General Keller E. Rockey for Iwo Jima in February 1945 and Haynes landed with the assault troops on Green Beach in the morning of February 19. Haynes participated in the planning and assault on Mount Suribachi and remained in combat area until the end of March. He was decorated with the Bronze Star Medal with Combat V for his bravery in action, and also received a Navy Presidential Unit Citation.