Schmeichel played at Manchester City with Hart.
The Dane, now playing in the Championship for Leicester, sees a keeper who can be the main man for City and England for years to come.
"For me, City have found the best keeper in England in Joe Hart," Schmeichel said.
Of all the keepers Schmeichel has worked with, Hart is among the best.
"Joe will be one of the world's best over the next 15 years," Schmeichel said.