[2] The event was won by 0.52 seconds by Kirani James of Grenada, earning the country its first Olympic medal.

Luguelín Santos's silver was the Dominican Republic's first medal in the men's 400 metres.

[2] The first round went largely to form, but defending champion LaShawn Merritt came to the meet injured and re-injured himself, unable to finish.

In the second heat, world champion Kirani James ran easily to win.

Heat 2 featured James and Jonathan Borlée, and double-amputee Pistorius' attempt to make the final.

Demetrius Pinder took the early lead down the back stretch, but reigning World Junior Champion Luguelín Santos (age 18) and reigning World Champion Kirani James (age 19) were in the lead coming off the turn.

Despite the Americans' string of 7 straight victories, it was the young Kirani James of Grenada who was favored going into this event.

[2] Brunei, Kazakhstan, Latvia, Macedonia, Myanmar, and Palestine appeared in this event for the first time.

The United States made its 26th appearance, most of any nation, having missed only the boycotted 1980 Games.

[a] Ahmed Mohamed Al-Merjabi was forced to scratch from this race after he injured his foot in a training session three days earlier.