Keita Kosugi

From the youth team of Shonan Bellmare, Kosugi went on trial with Djurgården in March 2024. On 22 March 2024, a couple of days after his 18th birthday, Kosugi signed with Djurgården on a four-year contract after two weeks of trial. He made his Allsvenskan debut against Elfsborg on 12 May 2024. Kosugi received limited play time in the first half of the season, as Djurgården also had left back Samuel Dahl in the squad. With Dahl sold to Roma, Kosugi's play time increased. From September to November, Kosugi started in eleven of the league matches. He scored his first goal for the club in a 1–1 tie against Kalmar FF on 6 October. During his first season in Djurgården, Kosugi made 14 league appearances and scored one goal. In December 2024, he scored the first goal in Djurgården's 2–1 away win over Víkingur of Iceland in the 2024–25 UEFA Conference League league phase. Djurgården started the 2025 season with the 2024–25 Svenska Cupen group stage where Kosugi, in the second match day, scored the equaling 2–2 goal against second-tier team Oddevold in the 90+5th minute, saving one point to Djurgården. On 18 December 2025, Kosugi signed a contract with German club Eintracht Frankfurt, effective 1 January 2026.

Kosugi was selected for Japan for the 2023 AFC U-17 Asian Cup in Thailand. He played all matches for the team that eventually won the cup with a 3–0 win against South Korea in the final. Kosugi was again selected for Japan for the 2023 FIFA U-17 World Cup later in the year. He played four matches for during the tournament in Indonesia. In May 2024, Kosugi was called up for the 2024 Maurice Revello Tournament with the Japan national under-20 football team.

Kosugi was born on 18 March 2006 in Kamakura, Japan. As a youth player, Kosugi joined the youth academy Nishikamakura SC, of Kanagawa, Japan. Subsequently, he joined the youth academy of Japanese side Shonan Bellmare.

In a 2024 interview, Kosugi stated that he saw Yuto Nagatomo as football role model.