Both McCain´s father and paternal grandfather, John Sidney McCain, Sr., were four-star admirals and his father rose to command all the U.S. naval forces in the Pacific. 

McCain spent his childhood and adolescent years moving between naval bases in America and abroad. He attended Episcopal high School, a private preparatory boarding school in Alexandria, Virginia, graduating in 1954.

Following in the footsteps of his father and grandfather, McCain graduated from the Naval Academy at Annapolis in 1958. He also graduated from flight school in 1960.

With the outbreak of the Vietnam War, McCain volunteered for combat duty and began flying carrier-based attack planes on low-altitude bombing runs against the North Vietnamese. He escaped serious injury on July 29, 1967, when his A-4 Skyhawk plane was accidentally shot by a missile on board the USS Forestal, causing explosions and fires that killed 134.

On October 26, 1967, during his 23rd air mission, McCain´s plane was shot down during a bombing run over the North Vietnamese capital of Hanoi. He broke both arms and one leg during the ensuing crash. McCain was moved to Hoa Loa prison, nicknamed the “Hanoi Hilton,” on December 9, 1969. 

His captors soon learned he was the son of a high-ranking officer in the U.S. Navy and repeatedly offered him early release, but McCain refused, not wanting to violate the military code of conduct and knowing that the North Vietnamese would use his release as a powerful piece of propaganda.

McCain eventually spent five and a half years in various prison camps, three and a half of those in solitary confinement, and was repeatedly beaten and tortured before he was finally released, along with other American POWs, on March 14, 1973, less than two months after the Vietnam cease fire went into effect. McCain earned the Silver Star, Bronze Star, Purple Heart and Distinguished Flying Cross.

Though McCain had lost most of his physical strength and flexibility, he was determined to continue serving as a naval aviator. After a painful nine months of rehabilitation, he returned to flying duty, but it soon became clear that his injuries had permanently impaired his ability to advance in the Navy. 

His introduction to politics came in 1976, when he was assigned as the Navy´s liaison to the U.S. Senate. In 1981, after marrying his second wife, Cindy Hensley, McCain retired from the Navy, and moved to Phoenix, Arizona. While working in public relations for his father-in-law´s beer distribution business, he began establishing connections in politics.