Saudi Arabia and South Africa each earned their first medals in the men's 400 metres hurdles, as Hadi Souan Somayli took silver and Llewellyn Herbert received bronze.

It had been introduced along with the men's 200 metres hurdles in 1900, with the 200 being dropped after 1904 and the 400 being held through 1908 before being left off the 1912 programme.

However, when the Olympics returned in 1920 after World War I, the men's 400 metres hurdles was back and would continue to be contested at every Games thereafter.

Mori had won the 1999 World Championship, but Angelo Taylor of the United States and Llewellyn Herbert of South Africa were the favorites.

Each National Olympic Committee was permitted to enter up to three athletes that had run 49.90 seconds or faster during the qualification period.