Swimming at the 2020 Summer Olympics – Men's 100 metre freestyle

It was the event's 28th appearance, having been held at every edition except 1900.

Defending champion Kyle Chalmers of Australia is expected to return, as are fifth-place finisher Duncan Scott of Great Britain and sixth-place finisher Caeleb Dressel of the United States. Dressel is the two-time reigning World Champion (2017 and 2019), with Chalmers the runner-up in 2019.

Labelled the "next Michael Phelps"[3] following his breakthrough four years ago at the 2017 World Championships, the U.S.' megastar Caeleb Dressel finally won his first individual Olympic title. Dressel used his signature explosive start to gain a strong advantage on the field and touch first at the 50, before narrowly holding on in the final lap to clock a new Olympic record of 47.02.

While Australia's defending Olympic champion Kyle Chalmers stormed home in the last 50, he could not overtake Dressel down the stretch, relegating him to silver by 0.06 seconds. Russia's Kliment Kolesnikov turned first at the halfway mark 0.10 seconds ahead of Dressel, though could not hang on with the finishing speed of Dressel and Chalmers, claiming bronze in 47.44.

French swimmer Maxime Grousset could not emulate the feats of his compatriot Alain Bernard, the 2008 Olympic Champion, slipping off the podium to fourth place. Korea's Hwang Sun-woo (47.82) and Italy's Alessandro Miressi (47.86) followed Grousset in fifth and sixth. Romanian 16-year old David Popovici (48.04) was unable to replicate his stunning 47.30 from earlier in the year, falling to seventh while Hungary's Nandor Nemeth (48.10) rounded out the championship field.

The medals for the competition were presented by Canada's Dick Pound, IOC member, and the gifts were presented by Senegal's Mouhamedou Diop, FINA Bureau Member.

The Olympic Qualifying Time for the event is 48.57 seconds. Up to two swimmers per National Olympic Committee (NOC) can automatically qualify by swimming that time at an approved qualification event. The Olympic Selection Time is 50.03 seconds. Up to one swimmer per NOC meeting that time is eligible for selection, allocated by world ranking until the maximum quota for all swimming events is reached. NOCs without a male swimmer qualified in any event can also use their universality place.[2]

The competition consists of three rounds: heats, semifinals, and a final. The swimmers with the best 16 times in the heats advance to the semifinals. The swimmers with the best 8 times in the semifinals advance to the final. Swim-offs are used as necessary to break ties for advancement to the next round.[4]

Prior to this competition, the existing world and Olympic records were as follows.

The following record was established during the competition:

The schedule is a three-day schedule, with each round on separate days.[1]

All times are Japan Standard Time (UTC+9)