KNOCK OUT Early career Ryusei made his professional debut against Naoki Iijima at Suk Wan Kingthong on April 7, 2019. He won the fight by a first-round knockout. Ryusei was next booked to face Shoi at REBELS 62 on August 10, 2019. He won the fight by a first-round knockout. Ryusei made his debut with
KNOCK OUT, the REBELS sister organization, against Miki Urabayashi at KNOCK OUT CHAMPIONSHIP.1 on February 11, 2020. He won the fight by a second-round technical knockout. Ryusei next faced Hiroto Sameshima at Suk Wan Kingthong Rookies on July 19, 2020. He won the fight by a third-round technical knockout. Ryusei faced Yuki Chiba at REBELS 65 on August 30, 2020. He won the fight by a first-round knockout, after knocking Chiba down three times by the 1:59 minute mark of the opening round. Ryusei was then booked to face KotaroZLS at REBELS 69 on December 6, 2020. He knocked Kotaro out with a head kick, only 51 seconds into the fight. Ryusei faced Takeru Owaki at KNOCK OUT ～The REBORN～ on March 13, 2021. He won the fight by unanimous decision, the first decision win of his professional career. One judge scored the fight 30–28 in his favor, while the remaining two judges awarded him all three rounds of the bout. Ryusei made his third KNOCK OUT appearance against Ryuta Inoue at KNOCK OUT EX 2021 vol.4 on August 22, 2021. He won the fight by a first-round technical knockout, forcing the referee to step in with a flurry of punches at the 2:00 minute mark.
Black Featherweight champion Ryusei's undefeated 8–0 run earned him the chance to fight Ginji for the inaugural
KNOCK OUT Black Featherweight title at KNOCK OUT 2021 vol.5 on October 29, 2021. He utilized his height and reach advantage to win the fight by unanimous decision, with all three judges awarding him the first and the second round on their scorecards. Following this victory, eFight named Ryusei their October 2021 "Fighter of the Month". The fight was ruled a
split decision draw after the first three rounds, with one judge scoring the fight 30–29 for Ryusei, while the remaining two judges scored it as an even 29–29 draw. An extra fourth round was contested, after which Ryusei was awarded the split decision. Ryusei made his
Rizin FF debut against Kaishi at
Rizin 37 - Saitama on July 31, 2022. He won the fight by a third-round knockout, stopping Kaishi with a combination of a left hook and a flying knee. Ryusei faced Yukinori Ogasawara at KNOCK OUT 2022 vol.5 on September 23, 2022. It was Ryusei's first fight following his departure from TRY HARD gym. Ryusei next faced Gu Taewon at KNOCK OUT 2022 vol.7 on November 19, 2022. He won the fight by a second-round head kick knockout. Ryusei faced Dawsakorn Mor.Tassanai at INOKI BOM-BA-YE x Ganryujima on December 28, 2022, in a ganryujima rules bout, which was contested in
MMA gloves and allowed for throws and chokes. Ryusei won by first round knockout with a left hook to the body only 31 seconds into the bout. Ryusei was expected to face Yodkitsada Yuthachonburi at KNOCK OUT 2023 SUPER BOUT BLAZE on March 5, 2023. Yodkitsada withdrew on February 8 and was replaced by the
Rajadamnern Stadium super bantamweight champion Petchsansab SorJor Tongprajin. The fight was ruled a majority decision draw after the first three rounds, with one judge scoring the bout 30–28 for Ryusei, while the remaining two judges scored it as an even 29–29 draw. Ryusei was awarded a unanimous decision, 10–8 on all three scorecards, after an extra round was contested. Ryusei faced Qumuxifu in a -59 kg catchweight bout at KNOCK OUT 2023 vol.2 on June 11, 2023. The fight was ruled a unanimous decision draw, following the first three rounds, with three even scorecards of 28–28. Although Ryusei was able to win the second and third rounds 10–9 with all three judges, Qumuxifu was awarded a 10–8 in the opening round, as he was able to knock the champion down with a right hook. Ryusei was declared the winner by unanimous decision, after an extra fourth round was contested. Ryusei faced Facu Suarez at KNOCK OUT 2023 vol.6 on December 9, 2023. He won the fight by a third-round knockout. Ryusei was expected to face
Kyo Kawakami at KNOCK OUT 2024 vol.1 on February 25, 2023. The bout was postponed for KNOCK OUT 2024 vol.2 on April 27, 2024, as Ryusei withdrew due to illness on February 23. The fight was reschedule for KNOCK OUT 2024 vol.2 on April 27, 2024. Ryusei won the fight by unanimous decision. Ryusei was scheduled to face
Kotaro Yamada at KNOCK OUT 2024 SUPER BOUT BLAZE on June 23, 2024. Yamada was replaced by Taimu Hisai due to injury and the bout was turned into a title fight for the inaugural Super Featherweight belt. Ryusei lost the fight by unanimous decision. Ryusei vacanted the KNOCK OUT Black Featherweight title on 11 July 2024 in order to move up in weight. Ryusei faced Braian Gavio for the vacant ISKA K-1 World Super Featherweight title at KNOCK OUT K.O CLIMAX 2024 on December 30, 2024. Ryusei won the fight by unanimous decision.
ONE Championship/KNOCK OUT On January 31, 2025, it was announced that Ryusei signed with
ONE Championship and he made his debut against Suriyanlek Por.Yenying on March 23, 2025, at
ONE 172. Ryusei faced Lom-Isan ReonGym at Kickboxing Fes. GOAT on October 30, 2025. He won the fight by unanimous decision, after knocking his opponent down in the third round. Ryusei faced
Shuhei Kumura at KNOCK OUT 60 on December 30, 2025. He won the fight by a second-round knockout. ==Titles and accomplishments==