The men's 400 metres hurdles was the longer of the men's hurdle races in the Athletics at the 1964 Summer Olympics program in Tokyo. It was held on 14 October, 15 October, and 16 October 1964. 39 athletes from 26 nations competed, with 1 more not starting in the first round. The maximum number of athletes per nation had been set at 3 since the 1930 Olympic Congress. The first round was held on 14 October, with the semifinals on 15 October and the final on 16 October. The event was won by Rex Cawley of the United States, the nation's sixth consecutive and 11th overall victory in the men's 400 metres hurdles. For the first time since 1952, the Americans did not sweep the event. John Cooper earned Great Britain's first medal in the event since 1928 with his silver; Salvatore Morale took Italy's first-ever medal in the 400 metres hurdles with his bronze.
Takatoshi Abe is a Japanese track and field athlete who competes in the 400 metres hurdles. He is the reigning Asian champion in the event.
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.
Diego Armando Palomeque Echavarría is a Colombian sprinter.
Yadisleidy Pedroso is an Italian hurdler. She competed at the 2020 Summer Olympics, in 400 m hurdles.
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.
Wenda Nel is a South African athlete specialising in the 400 metres hurdles. She competed at the 2011 World Championships reaching the semifinals.
Devynne Ashtyn Charlton is a Bahamian athlete specialising in the 100 metres hurdles.
Antonio Alkana is a South African hurdler. He competed in the 110 metres hurdles event at the 2015 World Championships in Beijing narrowly missing the semifinals. In addition, he won the gold at the 2015 African Games. He also competed in the men's 110 metres hurdles at the 2020 Summer Olympics.
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.
Lucas da Silva Carvalho is a Brazilian sprinter specialising in the 400 metres. He represented his country at the 2017 World Championships without qualifying for the semifinals. He was also an unused reserve runner for the Brazilian 4 × 400 metres relay at the 2016 Summer Olympics. He competed at the 2020 Summer Olympics.
Jacob Paul is a British hurdler who won the 400 metres hurdles event at the 2019 British Athletics Championships. He competed for England at the 2018 Commonwealth Games in Gold Coast, Australia.
Gerald David Drummond Hernández is a Costa Rican athlete specialising in the 400 metres hurdles. He has won multiple medals at regional level. In addition, he is his country's national record holder in the event. He competed at the 2020 Summer Olympics.
Emmanuel Kipkurui Korir is a Kenyan middle-distance runner. He is the 2020 Tokyo Olympic and 2022 World champion in the 800 metres. Korir won the silver medal in the event at the 2018 African Championships in Athletics.
The women's 400 metres hurdles event at the 2020 Summer Olympics took place between 31 July and 4 August 2021 at the Japan National Stadium. 39 athletes from 25 nations competed.
Alessandro Sibilio is an Italian sprinter and hurdler, who competes in the 400 metres hurdles and 400 metres. He won a gold medal at the 2018 IAAF World U20 Championships. He competed at the 2020 Summer Olympics, in 400 m hurdles.
Sokwakhana Zazini is a South African athlete specialising in the 400 metres hurdles. He won gold medals at the 2017 World U18 Championships and the 2018 World U20 Championships. In 2019, he won a silver medal at the Universiade.
Mozambique competed at the 2019 African Games held from 19 to 31 August 2019 in Rabat, Morocco. In total, athletes representing Mozambique won one gold medal, three silver medals and one bronze medal and the country finished 23rd in the medal table.
Mohamed Amine Touati is a Tunisian athlete specialising in the 400 metres hurdles. He won a bronze medal at the 2019 African Games. He competed at the 2020 Summer Olympics.
Jessie Knight is an English athlete specialising in the 400 metres hurdles.
Mozambique 
