Mao Hosoya was born on 7 September 2001 in Chiba and came through the Kashiwa Reysol youth ranks — a one-club career that has defined his rise. He made his J1 League debut as a teenager and helped Kashiwa win the J2 League title in 2019 before establishing himself as a senior starter.
Hosoya's breakthrough season came in 2023 with 31 J1 appearances and a remarkable 13 goals — making him one of the most prolific young J1 forwards. The 2024 season brought 32 J1 appearances with 6 goals and 3 assists, and 2025 saw him push back to 11 J1 goals from 36 league matches as he affirmed his status as Kashiwa's centre-forward of the present and future.
Hosoya represented Japan U-23 at the Paris 2024 Olympics — a campaign he started as the headline forward — and won the AFC U23 Asian Cup that same year. He also won the EAFF E-1 Football Championship with Japan in 2022 and again in 2025, scoring during the 2025 tournament.
A complete modern centre forward — strong link-up play, intelligent runs in behind, aerial presence and clinical finishing — Hosoya is one of the most reliable goal-scoring options in the J1 League and a frequent senior Japan call-up. With Ayase Ueda's place at the top of the depth chart, Hosoya is a natural No. 9 alternative, and his J1 form should keep him in the conversation for the 2026 World Cup squad.