Aseko spent the second half of last season on loan at Hannover 96, who had signed him from Bayern Munich in January 2025 on an 18-month loan deal that included a purchase option of €1m.
Hannover triggered that option at the end of the campaign, only for Bayern to immediately activate a buy-back clause and bring the German youth international back to Munich, before now selling him on to Frankfurt for a considerably larger fee. He has signed a contract with the Bundesliga club running to the summer of 2030, with an option for a further year.
Eintracht Frankfurt sporting director Markus Krösche said the club had been tracking Aseko for some time before completing the move.
"Noel Aseko was already part of the broader circle of Bayern's senior team two years ago for good reason," Krösche said. "Since then, he has proven in Hannover, in a physically demanding league, that he also has the physical attributes to take the next step.
"He also has a healthy offensive drive for his position as well as outstanding game understanding. We are convinced that Noel, with our coaching staff and in our environment, can fully develop his strengths in the Bundesliga. First and foremost, though, he needs to settle in quickly and integrate well."
Aseko made 33 appearances in all competitions for Hannover last season, scoring three goals and providing six assists as the 2. Bundesliga side pushed for promotion, performances that also helped establish him as a regular for Germany's Under-21 side. His rapid rise saw his market value climb sharply over the past year, reflecting the growing confidence in his ability to make an immediate impact at the top level of German football.
Bayern will make a substantial profit on the deal, having paid only €2.5m to trigger their buy-back clause with Hannover before selling Aseko on to Frankfurt for roughly five times that amount within weeks.
The midfielder came through Bayern's academy after joining from Hertha Berlin in 2022, but with competition for places in Vincent Kompany's squad intense, the club judged that a permanent departure offered the clearest path for him to continue developing with regular first-team football.