Okazaki has signed a four-year deal and moves to the King Power Stadium for an undisclosed fee.
The 29-year-old has scored 43 goals in 93 games for Japan – making him the third highest goalscorer in his country’s history.
Okazaki netted 12 goals in 32 appearances for the Bundesliga club last season, his second at the club since signing from Stuttgart in 2013.
He began his career with Shizuoka-based side Shimizu S-Pulse, scoring 42 goals before a 2011 move to Stuttgart.
Okazaki said: “I am very happy to be here. To play in the Premier League is my dream and I will make every effort to help the team here at Leicester City.
“I will do my best to show how I can play and try to make a lot of goals for the supporters.
“I watched every match (last season) in the Premier League not all of them are easy. There were hard games.
“In the last few games the crowd were great and the players responded. It was an amazing result at the end of the season.”