Matsushima won the U-15 boys' singles title at the 2021 ITTF World Youth Championships.[5] On that occasion, he also captured the U-15 boys' doubles title with Félix Lebrun and the U-15 mixed doubles title with Miwa Harimoto. In addition, Matsushima was a member of the Japanese U-19 boys' team, which won the bronze medal in the tournament.
At the senior level, Matsushima reached the men's singles final at the WTT Contender Rio de Janeiro 2023, where he was defeated by Mattias Falck in six games.[6] He was later selected as a member of the Japanese national team for the 2024 World Team Championships, recording three wins and one loss.[7] Matsushima was also named a reserve player for the Japanese men's team at the 2024 Summer Olympics.[8]
In 2025, Matsushima won the men's singles title at the All Japan Table Tennis Championships, defeating Tomokazu Harimoto in the semifinals and Hiroto Shinozuka in the final.[9] He later claimed the men's singles title at the WTT Contender Taiyuan.[10] In November, Matsuhima reached his best results on pro level in a span of two weeks. He first finished as runner-up at WTT Champions Montpellier, where he lost to Truls Möregardh and later crowned champion at WTT Champions Frankfurt, defeating local player Dang Qiu and earning his biggest title to date.[11][12] This victory also propelled him into the top ten of the men's singles world rankings.[4]
In 2026, Matsushima successfully defended his men's singles title at the All Japan Table Tennis Championships by once again defeating Tomokazu Harimoto and Hiroto Shinozuka in consecutive fashion.[13] Later that year at the ITTF World Cup, he reached the men's singles final after securing successive victories over Jang Woo-jin, Truls Möregårdh, and Lin Yun-ju.[14] In the final, he pushed Wang Chuqin to a deciding seventh game before ultimately falling to claim the silver medal.
