The men's 100 metres was the shortest of the sprint races at the 1908 Summer Olympics in London.

NOCs could enter up to 12 athletes,[1] The event was won by Reggie Walker of South Africa, the first time the gold medal went to a nation other than the United States.

Other notable entrants included John W. Morton of Great Britain, the four-time AAA Championships winner; Reggie Walker, the 1907 South African champion; and Knut Lindberg of Sweden, the unofficial world record holder.

[2] Austria, Belgium, Finland, the Netherlands, Norway, and South Africa were represented in the event for the first time.

The United States and Hungary were the only two nations to have appeared at each of the first four Olympic men's 100 metres events.

With a larger field than in 1904, the event expanded from two rounds to three: heats, semifinals, and a final.

Rector's Olympic record-tying time gave him a relatively easy victory in the first round.

Walker took the lead after about 50 metres and crossed the line about a yard in front of May to become the second sprinter to tie the Olympic record at the London Games.

Rector again won easily, tying the Olympic record for the second time.

Walker got off to a quick lead, but Rector caught him about midway through the race and passed him.