The 21-year-old midfielder becomes the sixth summer recruit – and the third new face since they returned to pre-season.
Cartwright, who has joined on a three-year deal, could be involved in tomorrow’s first friendly at FC United of Manchester.
A product of the Leicester youth academy, he was with the Foxes from the age of eight but did not make a senior appearance for the Foxes.
He spent last season on loan at Falkirk where he played 42 times for the Scottish Premiership side, scoring twice.
The first of those was a 25-yard equaliser in a 1-1 draw with Rangers in October that cost Russell Martin his job at Ibrox. Ironically, Martin is now in charge of Leicester.
Cartwright was sent off in Falkirk’s penalties defeat to Dunfermline in the Scottish Cup semi-finals.
Henry Cartwright scoring for Falkirk against Rangers (Image: PA)
He is described as a “gritty, steely” midfielder who performs at a high intensity and likes to press – attributes that will fit City’s style of play.
His contract at Leicester was up in the summer but the club triggered an option for a further year.
Cartwright said: “I am absolutely buzzing; this has been in the works for a while now, it is finally here, and I am delighted.
“The supporters are so loud here. It is not the first time I have been at Valley Parade; I played here in the EFL Trophy. I cannot wait to get started now.”
Graham Alexander had earlier revealed that the move had been “rumbling on for a while” and was delighted to get it done.
The City boss said: “We are delighted to bring Henry in and he will add a real competitive edge to our midfield.
“He has got great energy, has a very good passing range and an ambition to establish himself as a genuine first-team performer.”
