The Magpies are believed to have smashed the club's transfer record for the 22 year old.
County boss Ian McParland is delighted to have completed such a coup for the club and expects Schmeichel to play an integral role in an exciting future at Meadow Lane.
"It is a great signing for the club, obviously. He is one for now and one for the future," McParland said in the Nottingham Evening Post.
"Hopefully he will be here for a long time and become a firm fans' favourite and also help us up the league."