The 30-year-old Dutch international made the switch to the Etihad Stadium in August 2020 and went on to rack up 177 appearances during his time in Manchester.
Across those six seasons, Ake collected 12 major honours: four Premier League titles, a Champions League, a FIFA Club World Cup, two FA Cups, two League Cups, a Community Shield and a UEFA Super Cup.
His first two years in England were disrupted by injury, yet he still played a role as City claimed successive Premier League crowns in 2020/21 and 2021/22, and lifted the League Cup after beating Tottenham at Wembley.
By 2022/23, Ake had become central to City's Treble-winning campaign, featuring 41 times in all competitions.
He was a mainstay at left-back during the club's Champions League run that year, culminating in the famous night in Istanbul when City were crowned European champions for the first time.
The following season brought more silverware, with Ake appearing in both the UEFA Super Cup final and the FIFA Club World Cup final, as City became the first English club to win the Premier League, FA Cup, Champions League, Super Cup and Club World Cup within a single calendar year.
He then helped the club retain the league title in 2023/24, as City made history as the first men's team in English top-flight football to win four titles in a row.
Ake also played his part in beating rivals Manchester United to the 2024 Community Shield, before fitness problems limited his involvement through 2024/25, a season City nonetheless finished strongly enough to secure Champions League qualification for a 15th consecutive year.
In what proved his final season at the club, Ake helped secure two more trophies, starting in City's Carabao Cup final win over Arsenal and playing a part in their FA Cup final victory against Chelsea.
Beyond his defensive contribution, Ake also chipped in going forward, scoring 10 goals across his Etihad career.
"It's been a privilege to represent Manchester City over the past six years and I'm so grateful to have been part of a special team," said Ake.
"I've grown so much here – as a player and a person and I'm thankful for the time I've had at the club."
"I'll always cherish the memories, particularly of winning the Treble, being part of all four Premier League titles in a side that made history and triumphing in the Carabao Cup and FA Cup in my final season at the club."
"While I'm moving on, I'm very proud of everything we've achieved together and City will always be special to me."
City's Director of Football Hugo Viana led the tributes to the departing defender.
"There's no doubt that Nathan has been a key part of our success over the past few years," said Viana.
"Whenever he stepped onto the pitch, he always gave everything as well as being hugely dependable for the team. He's also shown versatile qualities – arriving as a centre-back but excelling at left-back including in our Treble-winning season of 2022/23."
"At the training ground, he was an outstanding, model professional who set high standards for everyone around him and this has no doubt contributed to the environment that we have now at the CFA."
"We would like to thank Nathan for his many contributions and we wish him the very best in his next chapter."