Ryo Germain

Ryutsu Keizai University

On 25 December 2017, won the championship final. He also scored 11 goals in 22 games in the Kanto University League.

Vegalta Sendai

After his graduation from Ryutsu Keizai University in 2017, Ryo Germain joined J1 League club Vegalta Sendai as a Special Designated Player. On 23 July 2017, he scored a penalty in a friendly match against Vissel Kobe. On 27 March 2018, he was promoted to the first team. On 24 December 2018, it was announced that his contract was renewed for the 2019 season.

Yokohama FC

After three seasons with the Tōhoku outfit, Germain joined J1 League club Yokohama FC in 2021.

Júbilo Iwata

In 2022, he joined Júbilo Iwata after 36 appearances and just 3 league goals for Fulie. He signed a new contract for the 2024 season. On 1 March 2024, Germain scores four goals against Kawasaki Frontale at Uvance Todoroki Stadium by Fujitsu and won 5-4 for his team in Matchweek 2 of 2024 J1 League. On 17 March 2024, he was the J1 League top scorer for the third week in a row after scoring against Gamba Osaka. His performances led him to win the Konami Monthly MVP award for April. He left from the club after relegation from J1 in 2024.

Sanfrecce Hiroshima

On 25 December 2024, Germain was announced as the newest signing for J1 club, Sanfrecce Hiroshima for the 2025 season.

Germain made his debut for Japan on 7 July 2025 during a 6–1 win against Hong Kong during the 2025 EAFF E-1 Football Championship. During this match, he became the first Japanese player to score four goals during their international debut since Takeo Wakabayashi achieved the same feat in 1930, and the first player of any nationality since Stan Mortensen achieved the feat in 1947. Germain also scored a goal in the final against rival South Korea to help Japan win their third EAFF title.

Ryo Germain was born in Atsugi, Kanagawa to an American father and a Japanese mother.