Andrzej Stanisław Badeński was a Polish sprinter who specialized in the 400 metres. He won a bronze medal in that event at the 1964 Summer Olympics, and won the gold medal in that event at the European Indoor Championships in 1968 and in 1971.
Louis Jacobus van Zyl, better known as L. J. van Zyl, is a South African athlete competing in the 400 metre hurdles. He is the South African record holder in the event with a personal best of 47.66 seconds, which he achieved twice, three months apart. His time ranks him in the all-time top 25. He is a three-time African Champion in the event and competed for his country at the 2008, 2012 and 2016 Summer Olympics.
Rabah Mahhamed Yousif Bkheit is a Sudanese-born British track and field athlete, who initially competed for Sudan before obtaining British citizenship.
David Kitur is a retired Kenyan runner, who specialised in 400 metres.
Simon Kemboi is a retired sprinter from Kenya. He specialised in 400 metres. He is a World Championships and African Championships medalist, and competed at the Olympics.
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.
Anna Vasylivna Ryzhykova, nee Yaroshchuk is a Ukrainian track and field athlete who specialises in the 400 metres hurdles. At the European Athletics Championships, she won silver medals in 2012 and 2018, and bronze in 2022. Ryzhykova placed fifth at the 2020 Tokyo Olympics.
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.
Karsten Warholm is a Norwegian sprinter who competes in the 400 metres and 400 m hurdles. He is the 2020 Tokyo Olympic champion, a three-time world champion and the world record holder in the latter event.
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 when he won the event at the 2016 Olympics.
Matthew Hudson-Smith is a British track and field sprinter who specialises in the 400 metres. He holds, as of July 2024, the British and European record, running a personal best of 43.74 seconds for the distance at the London Diamond League. He was the 2018 European Champion in 400 metres, and a member of the gold-winning teams in the 4 x 400 metre relay at the 2014 European Athletics Championships, with Great Britain and 2014 Commonwealth Games with England.
Janieve Russell is a Jamaican track and field athlete who competes mainly in the 400 metres hurdles and the 400 metres sprint. She won an Olympic bronze medal in the 4 × 400 m relay in Tokyo 2021, where she also finished fourth in the 400m hurdles final in a personal best of 53.08 secs. She is a four-time Commonwealth Games gold medallist, winning the 400m hurdles title in 2018 and 2022, and the 4 × 400 m relay in 2014 and 2018. She has also won two relay silvers at the World Championships and a relay gold at the World Indoor Championships.
Luiz Altamir Lopes Melo is a Brazilian swimmer.
Abderrahman Almoubarrake Samba Alsaleck is a Qatari male track and field athlete who specialises in the 400 metres hurdles. He was born and raised in Saudi Arabia but chose to represent Mauritania – his father's homeland – before eventually switching allegiance to Qatar and moving to Doha in 2015. He became eligible to compete for his adopted country in May 2016. He was the second person to run the 400m hurdle event in less than 47 seconds.
Christopher O'Donnell is an Irish track and field athlete competing in sprinting events. He was part of the Irish Mixed 4x400m team who won a gold medal at the European Athletics Championships in 2024. He represented Ireland at the 2020 Summer Olympics in the Mixed 4 × 400 m relay where he was part of the first ever Irish team to run in an Olympic final, and was also part of the team who reached the final of the 2022 and 2023 World Championships. He is the current Irish U20 record holder in the 400m, his personal best of 45.26 seconds sits joint-2nd on the Irish all-time list and he is a 5-time National 400m champion.
Jonathan Jones is a sprinter from Barbados.
Elija Godwin is an American athlete who specialises in the 400 metres.
Sean Bailey is a Jamaican athlete.
Alexander (Alex) Beck is an Australian Olympic athlete. He is a three time defending National champion.
Imaobong Nse Uko is a Nigerian athlete. She competed in the mixed 4 × 400 metres relay event at the 2020 Summer Olympics. The 17-year-old won the 400 metres at the 2021 World Under 20 Championships.
Sudan 
