Sakai, 69, was a runner but never competed in the Olympics. He was chosen to light the cauldron for symbolism. Sakai was born on Aug. 6, 1945, the day an atomic bomb was dropped on Hiroshima.
Watch Sakai light the 1964 Olympic cauldron at the 22-minute mark of this video.
Sakai later won medals at the 1966 Asian Games and went into a career as a TV journalist.
Tokyo will host the Olympics for the second time in 2020.