The Italy goalkeeper is confident his grounding with AC Milan and PSG has him ready for City and the Premier League.
“I’m really happy and excited to be here at one of the best clubs in the world,” Donnarumma told City's website.
“This is a club with a lot of history behind it and is hungry for victory.
“I know there is a lot of responsibility, but I’m proud to help the club continue winning together.
“For sure they (AC Milan and PSG) helped me in my growth a lot. I won a lot in my career so I will always be thankful to them for everything they gave me. “However, I am fully focused on my new challenge here now to make history here and become a symbol for the city and for the club
“But most of all to make the fans proud and win a lot of trophies together as it’s a historic club and deserves to be as high as possible.
“I’m proud to be here and happy about the choice I’ve made, and I hope I will make history here and win as many trophies as possible, that is my goal.”