The 46-year-old Italian, who left Chelsea by mutual consent on January 1 after 18 months in charge, is the natural succession choice at the Etihad.
He served as Guardiola's first-team assistant during the club's 2022-23 treble-winning campaign, having previously managed Manchester City's development squads, and the appointment represents a continuation of the club's footballing identity rather than a break from it.
Maresca's brief but eventful spell as Chelsea head coach produced a Conference League title and a Club World Cup, as well as a fourth-place Premier League finish before his departure amid reported friction with the club's ownership over transfer decisions and squad management. He has been without a club since January.
The two clubs have since drawn closer together in other ways, with Maresca likely to reconnect with several players he worked with at Stamford Bridge. Reports suggest as many as four Chelsea players could follow him to Manchester, though no names have been formally confirmed.
Guardiola will be honoured with an open-top bus parade through Manchester following Sunday's final Premier League match against Aston Villa, celebrating both the Carabao Cup and FA Cup trophies won this season.
The question of whether his name will be attached to the newly expanded North Stand at the Etihad remains under consideration, though Guardiola himself dismissed the idea when asked about it directly.
Maresca is expected to begin pre-season preparations with the squad in early July after the conclusion of the World Cup.