The 20-year-old, who spent last season on loan at league rivals Grimsby, becomes Darren Way’s first signing of the summer.
Graduating from Aspire Academy, run by Dulwich Hamlet, the pacey attacker was scouted by the Canaries before signing a professional contract in 2016.
After scoring eight goals in 33 appearances for City’s Under-23s in 2016/17, Jaiyesimi enjoyed his first taste of senior football on loan at Blundell Park last season making 35 appearances and scoring once.
Penning a new deal in Norfolk until at least 2020, the winger – who can also operate in attacking midfield or as a striker – will join up with Town when pre-season commences at the end of this month.
All at YTFC wish Diallang all the best during his time with the Glovers.