Despite having twelve months remaining on his Etihad deal, City sanctioned the German's departure ahead of Turkey's transfer deadline on 12 September. The decision reflects Pep Guardiola's evolving squad requirements and Gündogan's desire for regular football.
The Gelsenkirchen-born playmaker leaves with a fantastic legacy at the club. Across 358 appearances, he netted 65 goals and established himself as one of Guardiola's most trusted lieutenants. His seven-year association with City yielded five Premier League titles and that memorable Champions League triumph in Istanbul.
"Manchester City will always hold a special place in my heart," Gündogan reflected on his departure. "We achieved incredible things together, particularly during the treble-winning campaign when I had the honour of captaining the team.
"Lifting the Champions League in Istanbul was extraordinary - especially meaningful given my Turkish heritage. City will continue winning trophies, and I'll be watching from Turkey, a country close to my heart."
Gündogan's City journey began in 2016 when Guardiola identified him as his priority signing from Borussia Dortmund. After seven successful seasons, Barcelona lured him away on a free transfer in 2023. However, his Catalonian adventure lasted just one campaign before he returned to Manchester last August.
His second spell proved less fruitful. Though he featured regularly - making 33 league appearances - City endured a disappointing campaign by their standards, finishing third behind Arsenal and Liverpool. The midfielder's influence waned as younger players emerged, prompting both parties to consider a fresh start.
Hugo Viana, City's director of football, paid tribute to the departing German. "İlkay's name will forever be linked with Manchester City's golden era. His contribution to our success cannot be overstated."
For Galatasaray, securing Gündogan represents a significant coup. The Turkish champions gain a world-class operator with vast experience in elite competitions. His familiarity with Turkish culture - his parents emigrated from Turkey to Germany - should ease his transition.
The move also suits Gündogan's career timeline. At 34, he seeks consistent minutes ahead of what may be his final international tournament cycle. Galatasaray's participation in European competition provides the perfect stage for him to showcase his enduring quality.
City's willingness to release Gündogan reflects their squad's evolution under Guardiola. With promising youngsters pushing for opportunities and new signings settling in, Pep seemed comfortable sanctioning his departure.
Gündogan's departure closes another chapter in City's recent history. From Yaya Touré to David Silva, to Kevin De Bruyne, the club has grown accustomed to bidding farewell to midfield maestros who helped build their modern success. His legacy, however, remains secure - a cultured performer who thrived when it mattered most, and a top bloke off the pitch.