The Spaniard has signed a five-year contract which will keep him at the Etihad Stadium until 2025 in a deal worth a reported £20.8m.
Torres joins the former Premier League champions as a replacement for Leroy Sane, who left for Bayern Munich earlier this summer.
"I am so happy to be joining City. Every player wants to be involved in attacking teams and Manchester City are one of the most attacking in world football," Torres told the club's official website.
"Pep [Guardiola] encourages a really open, aggressive style, which I love, and he is a manager with a proven track record of improving players. To have him overseeing my development is a dream.
"City have won plenty of trophies in the last 10 years and I hope I can play a role in continuing that success."
Director of football Txiki Begiristain added: "We have followed Ferran's progress closely and have been very impressed.
"He is young and still developing, but his technical qualities are exactly what we are looking for in a winger. He is quick, direct, can create space with one movement and is capable of producing match-winning moments.
"I feel this is the perfect place for him to develop and with Pep in charge he can take his game to the next level."
Torres scored six goals and created eight more in 44 appearances across all competitions this season. body check tags ::