[1] The maximum number of athletes per nation had been set at 3 since the 1930 Olympic Congress.

Ulis Williams was the 1962 and 1963 AAU champion, but Mike Larrabee matched the world record to win the U.S. Olympic trials.

Other contenders included 1962 European champion Robbie Ian Brightwell of Great Britain and Wendell Mottley of Trinidad and Tobago.

[2] Hong Kong, Iran, the Ivory Coast, Senegal, and Tanzania appeared in this event for the first time.

The United States made its fifteenth appearance in the event, the only nation to compete in it at every Olympic Games to that point.

The top four runners in each semifinal heat advanced, making an eight-man final.