In 2014, at the
2014 European Junior Championships, Greenbank won gold medal in 200 m backstroke. He then competed at the
2014 Youth Olympics in
Nanjing taking bronze in 200 m backstroke and gold in 4 × 100 m freestyle (with
Duncan Scott, Miles Munro, Martyn Walton). In June 2015, Greenbank competed at the inaugural
2015 European Games in
Baku, He won 2 gold medals in (200 m, 100 m backstroke) and breaking a new Junior World record in 200 m backstroke at the
2015 European Games clocking in 1:56.89. He also took silver medals in 4 × 100 m medley (with
Duncan Scott, Charlie Attwood, Charlie Attwood) and in 4 × 100 m mixed medley. On August 25–30, Greenbank won bronze in men's 100 backstroke at the
2015 World Junior Championships held in
Singapore.
2018–2019 At the
2018 Commonwealth Games held at the
Gold Coast,
Australia, Greenbank won a silver in the 4 × 100 m medley with
Adam Peaty,
James Guy and
Ben Proud. Greenbank won his first World Championships medal at the
2019 World Aquatics Championships held in
Gwangju, South Korea. He finished third in the
men's 200m backstroke, setting a personal best time. He was part of the team in the
men's 4 × 100 metre medley relay together with
Adam Peaty,
James Guy and
Duncan Scott. He started the race in the backstroke leg, and the team finished in a European record time of three minutes, 28.10 seconds to beat the United States, and won their first gold medal in the event in the World Championships. Greenbank was one of the 2019 individual world championship medal-winners who were pre-selected for the postponed
2020 Tokyo Olympics.
2020 At the
2020 European Championships held in Budapest in May 2021, Greenbank won a silver in
200 metre backstroke, as well as a gold in the
men's medley relay with Peaty, Guy and Scott.
2022 In June 2022, at the
2022 World Aquatics Championships, he won the silver medal in the
200 metre backstroke with a time of 1:55.16, finishing less than seven-tenths of a second behind gold medalist
Ryan Murphy of the United States and less than two-tenths of a second ahead of bronze medalist
Shaine Casas of the United States. He also won a bronze medal in the
4×100 metre medley relay, splitting a 53.81 to contribute to the final time of 3:31.31.
Commonwealth The first day of
swimming competition at the
2022 Commonwealth Games, Greenbank qualified for the semifinals of the
100 metre backstroke, ranking fourth in the preliminaries with a time of 54.55 seconds. In the semifinals later in the day, he swam a 54.23 to qualify for the final ranking fifth. On day two, he placed fifth in the final with a time of 54.29 seconds, finishing 0.51 seconds behind gold medalist
Pieter Coetze of
South Africa. Three days later, he ranked as the overall fastest swimmer in the preliminaries of the
200 metre backstroke with a time of 1:56.33 and qualified for the final. He placed fifth in the final with a time of 1:56.98. On day six of six, he swam the backstroke leg of the
4×100 metre medley relay in 54.28 seconds in the preliminaries, helping qualify the relay to the final ranking second in 3:35.88. In the final, Brodie Williams substituted in for him and he won a gold medal for his efforts in the prelims when the finals relay placed first in 3:31.80.
European Championships A little over one week later, at the
2022 European Aquatics Championships held in
Rome, Greenbank ranked fourth in the prelims heats of the
200 metre backstroke with a time of 1:57.81 and qualified for the evening semifinals. He swam a 1:57.07 in the semifinals, qualifying for the final ranking third. In the final, he won the bronze medal with a time of 1:56.15, finishing 0.53 seconds behind gold medalist
Yohann Ndoye-Brouard of
France. Five days later, on the final day of swimming competition, he helped placed fourth in the
4×100 metre medley relay, splitting a 54.28 for the backstroke leg of the relay to contribute to the final time of 3:33.60 and finishing 0.32 seconds behind the team from
Austria that won the bronze medal.
2024 After finishing second behind
Oliver Morgan in the
200 metres backstroke at the
2024 Aquatics GB Swimming Championships, Greenbank recorded a time that met the British Consideration criteria for a place at the
2024 Summer Olympics. He was subsequently named in the British team for the Olympics. Luke Greenbank competed at the
2024 Summer Olympics. In the Olympics, although he placed first in his heat in the 200 metre backstroke, he was disqualified due to staying underwater past the 15 metre mark.
2025 Greenbank finished second again behind Oliver Morgan in the 200 metres backstroke at the
2025 Aquatics GB Swimming Championships and earned selection for the
2025 World Aquatics Championships in Singapore. Subsequently, at the World Championships, he reached the final of the
200 metres backstroke. == References ==