On November 8, 1960, John F. Kennedy was elected president of the United States, defeating Richard Nixon in one of the closest national elections of the 20th century. At 43, Kennedy was (and remains) the youngest person elected to the office, and it was largely this quality in the man and his family — an engaging, youthful dynamism — that so captured the imagination of millions across the country and, ultimately, across the world.

As Kennedy and his team ran a heady, propulsive campaign unlike any America had seen, LIFE’s best photographers (Paul Schutzer, Alfred Eisenstaedt, George Silk, et al.) were there, chronicling the grind of never-ending public appearances and the quieter moments JFK spent with advisers, with Jackie, and — rarest of all — alone, with his own thoughts.

In the midst of this fraught and divisive election season, LIFE.com presents rare photos (most were never published in LIFE magazine) of an enigmatic, intensely ambitious man making history, as he and his entourage ushered in the poignantly brief American era known ever after as “Camelot.”