Wataru Endo was born on 9 February 1993 in Japan and began his professional career at J1 League club Shonan Bellmare. He established himself as a reliable defensive presence, scoring seven goals in 38 league matches as Shonan won the 2014 J.League Division 2 title and earned promotion back to the top flight.
Endo moved to Urawa Red Diamonds in 2016, where his career took a significant step forward. He scored the winning penalty in the 2016 J.League Cup final shoot-out and went on to claim the 2017 AFC Champions League — the most prestigious club honour in Asian football. A spell at Belgian side Sint-Truiden followed before he joined VfB Stuttgart in the Bundesliga, first on loan and then permanently. His four years in Germany proved highly productive; he topped the Bundesliga for most duels won and was regularly among the leading players for possession regained and tackles made. In May 2022 he scored a stoppage-time winner against 1. FC Köln that kept Stuttgart in the Bundesliga.
A composed, ball-winning defensive midfielder with strong game-reading ability, Endo signed for Premier League club Liverpool in August 2023 for £16 million. He scored his first Premier League goal in a 4–3 victory over Fulham in December 2023, was voted Liverpool's Player of the Month that same month, and went on to win the EFL Cup in 2024 and the Premier League title in 2024–25.
Endo made his international debut for Japan in August 2015 and has earned over 70 caps, captaining the side since June 2023. He appeared at the 2022 FIFA World Cup, where Japan reached the round of 16.