Jesus has been handed the number nine shirt at Arsenal, which has now been vacated following Alexandre Lacazette's departure on a free transfer and subsequent return to Lyon.
Jesus only had one year left on his contract with Man City and was understood to have also been on the radar of Tottenham Hotspur, Chelsea and Juventus before arriving at the Emirates.
Prior to Monday's announcement, leaked images and videos on social media showed Jesus conducting his media duties inside the Emirates last week, and Arsenal have now officially confirmed the South American's signing.
"We are delighted that we have secured the transfer of Gabriel. Everyone who knows football well, knows the qualities of Gabriel Jesus," Technical director Edu told the official Arsenal website.
"Gabriel is a player who we have admired for a long time now. He is 25 years old and an established Brazil international who has consistently demonstrated that he is a player at a very high level.
"We look forward to seeing him join up with his new teammates ahead of the new season. We all welcome Gabriel to Arsenal."
Manager Mikel Arteta added: "I'm very excited. The club has done a tremendous job to recruit a player of this stature. I know Gabriel personally very well, and we all know him well from his time in the Premier League and being really successful here.
"This is a position that's been on our radar for a long time now and we have managed to get a player that we all wanted, so I'm really happy."
During his five-and-a-half year stay at the Etihad, Jesus racked up 95 goals and 46 assists in 236 appearances for Pep Guardiola's side after arriving from Palmeiras in January 2017.
Jesus helped Man City win four Premier League titles, four EFL Cups, one FA Cup and two Community Shields, as well as reaching the final of the 2020-21 Champions League.
The Brazil international is believed to have signed a contract in the region of £220,000 per week, which will make him the Gunners' highest paid player for the 2022-23 season.
Jesus is set to link up with his new teammates for pre-season training later this month as the Gunners prepare for their first official friendly fixture with Nurnberg on July 8 before their trip to the United States for the Florida Cup.
The striker's first appearance at the Emirates Stadium in an Arsenal shirt could come on July 30 against Sevilla in the Emirates Cup before the Gunners kick off their Premier League campaign against Crystal Palace on August 5. body check tags ::