[2] Momota was born in Mitoyo, Kagawa Prefecture, and started playing badminton in the second grade of elementary school.

When he was in sixth grade he received his first title in the All Japan Elementary School Championship, winning the men's singles category.

Momota's presence was increasingly visible as he took part in a bigger race, the 2011 World Junior Championships held in Taipei, Taiwan.

He won all his matches during Japan's maiden Thomas Cup victory in 2014, playing second men's singles behind Kenichi Tago.

By winning that title, he became the first Japanese player to successfully capture a Superseries in the men's singles and currently holds the record as the youngest Super Series champion in that category.

He competed at the 2014 Asian Games in Incheon, South Korea, as well as the 2016 Badminton Asia Team Championships in Hyderabad, India.

However, due to a lack of his points, he was not qualified to play in the 2018 All England Open, a significant Super 1000 tournament which was held in March.

[3] On 28 April, he won the 2018 Asian Championships which was held in Wuhan, after defeating Chen Long of China in the finals with a score of 21–17, 21–13.

[4] Momota started the 2019 season by competing at the Malaysia Masters as the first seed, but his pace was stopped by Kenta Nishimoto in the first round.

[8] In April, Momota won his second Asian Championships title in Wuhan, China beating home favorite Shi Yuqi in three games 12–21, 21–18, 21–8.

[11] Momota closed his stellar 2019 year by winning his 11th title, the World Tour Finals by beating Indonesia's Anthony Sinisuka Ginting 17–21, 21–17, 21–14.

[16] Despite not being at his physical best, Momota pulled off a good show to beat the 2017 World Champion Viktor Axelsen of Denmark 24–22, 21–11 in the final.

[21] During 2020 Summer Olympics, again playing as top seed, Momota was knocked out in the group stage after losing to the unseeded South Korean Heo Kwang-hee.

[23] At the Thomas Cup in Aarhus, Denmark, Momota alongside Japanese team won the bronze medal.

[24] In October, he took part in the Denmark Open and finished in 2nd place to Viktor Axelsen in three games, 22–20, 18–21, and 12–21, in a match lasting an hour and thirty-three minutes.

[25] In November, Momota won his first title since his injury, the Indonesia Masters, defeating Anders Antonsen in straight games (21–17, 21–11) in a seemingly one-sided final.

[31] At the Malaysia Open, Momota made it through to his first final since winning the 2021 Indonesia Masters Super 750 event in November.

[32] After the match, Momota told reporters that Axelsen's "level" was higher than he expected, and that despite the loss, he was "very happy to be back here after all the difficult times" he had been through, adding that he "might be getting closer to the answer" that he was looking for.

[33][34] In the following week, Momota lost in the round of 16 at the Malaysia Masters to compatriot Kanta Tsuneyama, losing 16–21, 15–21 in 50 minutes.

[36] On the 18th April, Momota announced his retirement from the Japanese national team, with the 2024 Thomas Cup being his last international tournament.

[44][45] The Nippon Badminton Association secretary general Kinji Zeniya said it would “probably be impossible” for Momota to participate in the Rio 2016 Olympics, with frequent gambling being punishable by law with a prison sentence of up to 3 years.