The French defender has agreed a five year deal worth £150,000-a-week that will keep him at the Etihad until 2023.
The 23-year-old joins City from Athletic Bilbao to become Guardiola’s sixth signing of the season.
Laporte, who is regarded as one of the best young defenders in Europe, has set his sights on winning silverware.
He said: “I am very happy to be here. City are a Club with a lot of ambition and they are one of the best teams in Europe.