In 1942, Dole joined the United States Army's Enlisted Reserve Corps to fight in World War II, becoming a second lieutenant in the Army's 10th Mountain Division. In April 1945, while engaged in combat near Castel d'Aiano in the Apennine mountains southwest of Bologna, Italy, Dole was badly wounded by German machine gun fire, being hit in his upper back and right arm. As Lee Sandlin describes, when fellow soldiers saw the extent of his injuries, all they thought they could do was to "give him the largest dose of morphine they dared and write an 'M' for 'morphine' on his forehead in his own blood, so that nobody else who found him would give him a second, fatal dose."
Dole was transported to the United States, where his recovery was slow, interrupted by blood clots and a life-threatening infection. After large doses of penicillin had not succeeded, he overcame the infection with the administration of streptomycin, which at the time was still an experimental drug. He remained despondent, "not ready to accept the fact that my life would be changed forever." He was encouraged to see Hampar Kelikian, an orthopedist in Chicago who had been working with veterans returning from war. Although during their first meeting Kelikian told Dole that he would never be able to recover fully, the encounter changed Dole's outlook on life, who years later wrote of Kelikian, a survivor of the Armenian Genocide, "Kelikian inspired me to focus on what I had left and what I could do with it, rather than complaining what had been lost." Dr. K, as Dole later came to affectionately call him, operated on him seven times, free of charge, and had, in Dole's words, "an impact on my life second only to my family."
Dole recovered from his wounds at the Percy Jones Army Hospital. This complex of federal buildings, no longer a hospital, is now named Hart-Dole-Inouye Federal Center in honor of three patients who became United States Senators: Dole, Philip Hart and Daniel Inouye. Dole was decorated three times, receiving two Purple Hearts for his injuries, and the Bronze Star with "V" Device for valor for his attempt to assist a downed radioman. The injuries left him with limited mobility in his right arm and numbness in his left arm. He minimizes the effect in public by keeping a pen in his right hand.