He is now set to become a Borussia Monchengladbach player, becoming the latest in a long line of Japanese players to move to the Bundesliga in recent years.
Gladbach have announced that Uno has signed a contract running until 2030, with the transfer fee reported at a modest €500,000.
Sporting director Rouven Schroder praised the player's profile in a statement.
"Zento is a defensively-minded, tactically disciplined midfielder who is strong in duels and covers a lot of ground, with his greatest strengths coming in his work off the ball," Schroder said.
"After two seasons in the J-League and his first appearances for the Japan national team, the move to the Bundesliga is the next, but also demanding, step for him.
"We believe that Zento, with his character and ambition, will master this challenge, and we are looking forward to accompanying and supporting him on the way."
Uno himself explained his decision to join the club.
"I always wanted to play in the Bundesliga," he said. "Borussia is a big club, well known in Japan because of its Japanese players. When the offer came in, it was clear to me that I wanted to play for Borussia. I am very happy about this step and look forward to the new challenge."
Gladbach already had two Japanese players in their squad last season in Kota Takai, 21, and Shuto Machino, 26.
Takai is returning to the club following a loan spell at Tottenham Hotspur, meaning Uno will have Machino as a compatriot in the squad to help smooth his integration into life in Germany.
Uno joins as a defensive-minded six rather than a direct replacement for either of his new compatriots, giving Gladbach a different profile in central midfield as they continue to build a squad around several international playing styles.
The move continues a steady flow of talent from the J-League into the Bundesliga in recent seasons, with German clubs increasingly turning to Japan as a source of technically sound, tactically versatile players at relatively low cost.
It marks the first move outside Japan in Uno's career.