Pep Guardiola’s side had plenty of possession in the early stages and started to create opportunities with Semenyo seeing two attempts blocked, while Omar Marmoush got an unconvincing touch on the ball after the first of those.
Rodri then got off a header that was blocked by Joao Pedro, although the Cityzens were unable to test Robert Sánchez despite continuing to move the ball nicely.
João Pedro had an opportunity of his own at the other end, but he was marshalled well by Abdukodir Khusanov and slipped while hitting a shot that James Trafford routinely gathered.
Matheus Nunes squared the ball for Erling Haaland to touch the ball home in the 27th minute, but the goal was ruled out due to the right-back straying offside before being played through by Semenyo.
The Ghana international then jinked inside Marc Cucurella but blazed a horrible shot out for a throw, before Chelsea had their own period of control without testing the goalkeeper.
Erling Haaland eventually forced the game’s first notable save shortly before the break, as Sánchez instinctively turned his first-time strike behind.
Guardiola turned to Rayan Cherki ahead of the restart, and the France international was involved in creating an opportunity within two minutes, as he passed the ball out wide for Nico O’Reilly to deliver a cross that Semenyo headed over.
Rodri headed away Moisés Caicedo’s header at the other end after Trafford cheaply conceded a corner, and Wesley Fofana was unable to head Reece James’ cross goalward as Chelsea looked increasingly encouraged.
It was the sky blue side of Wembley that erupted in the 72nd minute, though, as Haaland’s cutback was met by an ingenious Semenyo flick that crept inside the far post.
Enzo Fernández came agonisingly close to providing an immediate response, but Manchester City stayed in front despite Sánchez denying Nunes and Cherki.
Ultimately, the Cityzens did enough to win their second Wembley final of the season, lifting the FA Cup for the eighth time in their history, while equalling the Blues’ tally and providing the perfect tone for the Premier League run-in.
In doing so, they condemn Chelsea to a fourth defeat from their last four FA Cup finals.
Flashscore Man of the Match: Antoine Semenyo (Manchester City)