Louis Yamaguchi

Born in La Garenne-Colombes, Paris to a French father and a Japanese mother, Thébault-Yamaguchi moved to Tokyo at six months old, and returned to France at the age of 16, joining FC Lorient's youth setup. On 16 June 2017, after finishing his formation, he moved to Spanish Segunda División B side Extremadura UD, being initially assigned to the reserves. Thébault-Yamaguchi made his professional debut on 3 September 2017, starting in a 1–0 Tercera División home lost against UD Montijo. He became a regular starter for the B-side during the following seasons, and ahead of the 2019–20 campaign, he was definitely promoted to the first team as a backup to Casto. Thébault-Yamaguchi made his professional debut on 3 November 2019, starting in a 3–1 home loss against Girona FC in the Segunda División. He left the club in the following July, as his contract expired, and joined Recreativo de Huelva in the third division on 11 August. After leaving Recreativo in July 2021, Thébault-Yamaguchi signed with J2 League club Mito HollyHock in January 2022. He made his club debut in a 2–1 loss to Thespakusatsu Gunma as the team's starting goalkeeper, replacing Shu Mogi. In January 2024, Thébault-Yamaguchi joined newly promoted J1 League club FC Machida Zelvia. He appeared in one match, a 1–1 (2–4) penalty shootout loss to the fifth-division University of Tsukuba team in the Emperor's Cup, before being sent on loan to Kawasaki Frontale. Yamaguchi made his club debut for Frontale in the J.League Cup…

Yamaguchi represented Japan at under-19, under-20 and under-23 levels. He was a member of the Japanese squad at the 2017 FIFA U-20 World Cup, and the squad that finished runners-up in the 2019 Toulon Tournament.

Kawasaki Frontale

AFC Champions League Elite runner-up: 2024-25