This is from Wikipedia.
As a child, John was known for a quick temper and an aggressive drive to compete and prevail. After World War II was over, his father stayed in the Navy, sometimes working political liaison posts; the family settled in Northern Virginia, and McCain attended the educationally stronger St. Stephen's School in Alexandria, Virginia from 1946 to 1949, where he began to develop an unruly, defiant streak. Another two years were then spent following his father to naval stations; altogether he attended about twenty different schools during his youth. In 1951, McCain enrolled at Episcopal High School in Alexandria, a top private school with a rigorous honor code. McCain earned two varsity letters in wrestling, and he excelled in the lighter weight classes. Gaining the nicknames "Punk" and "McNasty" due to his combative and fiery disposition, he enjoyed and cultivated that tough guy image . . . .