Martyn Joseph Rooney is an English sprinter who specialises in the 400 metres event. He reached the 400 m final at the 2008 Summer Olympics and won bronze in the 4×400 metres relay. A mainstay on the anchor leg of the Great Britain and England 4 x 400 metre relay teams, at the 2009 World Championships in Athletics he won a silver medal with the Great Britain relay team, and bronze in the 2015 and 2017 World Championships.
LaShawn Merritt is an American track and field athlete who competes in sprinting events, specializing in the 400 metres. He is a former Olympic champion over the distance and his personal best of 43.65 seconds makes him the ninth fastest of all time.
Christopher Clarke is an English elite athlete sprinter who has often represented Great Britain and Northern Ireland. At club level he represents Marshall Milton Keynes AC and is also higher claim to Newham and Essex Beagles A.C.
Rabah Mahhamed Yousif Bkheit (born 11 December 1986) is a Sudanese-born British track and field athlete, who initially competed for Sudan before obtaining British citizenship.
Deon Kristofer Lendore was a Trinidad and Tobago sprinter who specialised in the 400 metres. He won a bronze medal in the 4 × 400 metres relay event at the 2012 Summer Olympics, and won medals at the Pan American Junior Athletics Championships, World Athletics Championships and World Athletics Indoor Championships. Lendore died in a car collision in Texas, United States, on 10 January 2022.
Luguelín Miguel Santos Aquino is a Dominican sprinter, who specialises in the 400 m. He was the silver medallist in the event at the 2012 London Olympics at the age of eighteen. His personal best is 44.11 seconds.
Machel Cedenio is a Trinidadian sprinter specialising in the 400 metres. He represented his country at two outdoor and one indoor World Championships winning a silver medal in the relay at the 2015 outdoor edition. He competed at the 2016 Summer Olympics. He qualified for the final and came fourth with a new personal best of 44.01 seconds. This is the fastest fourth place time for the 400 metres.
Shaunae Miller-Uibo is a Bahamian track and field sprinter who competes in the 200 and 400 metres. She is a two-time Olympic champion after winning the women's 400 metres at the 2016 Rio Olympics and again at the 2020 Tokyo Olympics.
Nijel Carlos Amilfitano Amos is a Botswana middle-distance runner who competes in the 800 metres. He won the silver medal at the 2012 London Olympics, which was Botswana's first ever Olympic medal. Amos claimed gold medals at the 2014 Commonwealth Games and 2015 All-Africa Games. At the African Championships in Athletics, he took golds in 2014, 2016 and 2018.
Emily Diamond is a British track and field athlete, who competes in the 200 metres and 400 metres. Diamond came to prominence in her breakout season of 2016 when, following her first win at the British Championships over the 400 metres distance, she collected a gold medal in the 4 x 400 metres relay at the 2016 European Athletics Championships as part of the Great Britain team, followed by a bronze in the same discipline at the 2016 Summer Olympics.
David McKeon is an Australian competition swimmer. At the 2012 Summer Olympics in London, he competed in the men's 400-metre freestyle, finishing in 14th place in the heats, failing to reach the final.
Athletics at the 2016 Summer Olympics were held during the last 10 days of the games, from 12 to 21 August 2016, at the Olympic Stadium. The sport of athletics at the 2016 Summer Olympics was made into three distinct sets of events: track and field events, road running events, and racewalking events.
Amel Tuka is a Bosnian middle-distance runner who competes in the 800 metres. His achievements include a silver medal at the 2019 World Championships as well as a bronze medal at the 2015 World Championships. Tuka holds national records in the 400 m and 800 m disciplines. His personal best is 1:42.51 in the 800 metres.
Wayde van Niekerk is a South African track and field sprinter who competes in the 200 and 400 metres. In the 400 metres, he is the current world and Olympic record holder, having set the record in the Olympic finals. He also holds the world-best time in the 300 metres.
The men's 400 metres event at the 2016 Summer Olympics took place between 12 and 14 August at the Olympic Stadium. Fifty-three athletes from 35 nations competed. The event was won by Wayde van Niekerk of South Africa, the nation's second gold medal in the men's 400 metres. Kirani James of Grenada and LaShawn Merritt of the United States became the sixth and seventh men to win two medals in the event, but Michael Johnson remained the only man with two gold medals.
The men's 4 × 400 metres relay competition at the 2016 Summer Olympics in Rio de Janeiro, Brazil was held at the Estádio Olímpico João Havelange on 19–20 August.
Baboloki Tirelo Thebe is a Botswana track and field sprinter who specialises in the 400 metres. He was a silver medallist in the 200 metres at the 2014 Summer Youth Olympics. He reached the semi-finals at the 2014 World Junior Championships in Athletics. He made a breakthrough in the 400 m in May 2016 with a run of 44.22 seconds, placing him third on the global seasonal lists and moving him into the all-time top 30 for the event. He competed at the 2016 Summer Olympics. His personal best in 400 meters is 44.02, which he ran in July 2017
Lesotho sent a delegation to compete at the 2016 Summer Paralympics in Rio de Janeiro, Brazil, from 7 to 18 September 2016. This was the fifth time the country competed in the Summer Paralympic Games after it made its debut sixteen years prior at the 2000 Sydney Paralympics. The delegation to Rio de Janeiro consisted of two athletes: sprinter Sello Mothebe and discus thrower Litsitso Khotele. Mothebe originally came third in the heats of the men's 200 metres T12 and the men's 400 metres T12 events but he was retroactively disqualified for testing positive for a banned substance. Khotele ranked tenth in the women's discus throw F43–44 competition with a throw of 19.91 metres.
Ned Justeen Azemia is a Seychellois hurdler who specialises in the 400 metres hurdles. He is the current Seychellois record holder in the event. Azemia competed in the 2016 Summer Olympics in Rio de Janeiro in the 400 metres hurdles. He has also competed in two World Junior Championships, an African athletics championships and an African Youth Games. Azemia has also raced over the flat 400 metres distance.
The men's 400 metres event at the 2020 Summer Olympics took place between 1 and 5 August 2021 at the Olympic Stadium. Approximately fifty athletes were expected to compete; the exact number was dependent on how many nations use universality places to enter athletes in addition to the 48 qualifying through time or ranking. 48 athletes from 33 nations competed. The event was won by Steven Gardiner of the Bahamas, with Anthony Zambrano of Colombia taking silver. Those were the first medals in the men's 400 metres for each of those two nations. Kirani James of Grenada won his third consecutive medal in the event with his bronze, making him the first man to earn three medals in the 400 metres.
Botswana 
