After graduating from Harvard in 1940, Jack spent the fall at Stanford, doing some graduate work and basking in the California sun. In early 1941, as American entry into World War II loomed on the horizon, Jack was drafted into the military, but failed the physical tests necessary for admission to the navy and army as a result of his poor health and frail physique. Disappointed with his failure and eager to join his older brother, Joe Jr., who was already training to be a Navy pilot, Jack spent the spring and summer months rigorously training his body (think Rocky, but without the raw eggs). Unfortunately for Jack, his workout regimen didn't quite cut it—he was still deemed physically ineligible for military service. Most people would have probably stopped trying at that point, but Jack had one last trick left up his sleeve: Joe Sr. After contacting some of his father's friends in the military, Jack suddenly "passed" his medical exam and entered the Navy in October of 1941. Initially, Kennedy was assigned to desk jobs in Washington, D.C. and Charleston, South Carolina. Jack, however, was anxious to get a chance to really take part in the war. In 1942, he was transferred to a Patrol Torpedo boat training program, where he stood out among the other trainees for his commitment and leadership.
On 24 April 1943, Jack was asked to take command of an actual Patrol Boat (PT 109) near the Solomon Islands. Life in the South Pacific was smooth sailing until 2 August 1943, when a Japanese destroyer struck PT 109, killing two of Jack's men and severely injuring nearly everyone else on the crew. Though Kennedy sustained major back injuries in the collision, he conducted himself with courage, poise, and stoicism. After instructing his crew to abandon ship, Jack noticed that one of his men was barely conscious and clearly unable to swim. Despite his own excruciating back pain, Jack took the strap of the man's life jacket, held it between his teeth, and swam to shore, pulling his comrade the whole way.8 Jack and his men landed at Plum Pudding Island, battered and exhausted from their harrowing experience. Almost immediately, Kennedy began to explore the island and the surrounding area in search of help. Three days went by without any sign of life. Fortunately, on the fourth day, Jack encountered two natives and asked them to deliver a message he had ingeniously carved into the shell of a coconut. The two men brought the coconut to a military post, and Jack and his crew were rescued shortly thereafter.
For his military service, Kennedy was awarded a Purple Heart and Navy Medal. In August of 1944, two years after the PT 109 incident, the Kennedy family suffered another tragedy of war: the death of Joe Jr., who was killed when his plane, carrying over two tons of dynamite, suddenly exploded. Now that Joe Jr. was gone, Jack found himself next in line for the political career that Joe Sr. had always envisioned for his eldest son.