Kimonas Kokoroyiannis undertook the representation the season 2005 when the player was playing for Panionios in Super League.
Soon he became a basic member in the position of the left-back.Panathinaikos was interested in buying him but unfortunately the transfer was not made.Nevertheless,his appearances attracted the attention of Otto Rehhagel who calls him for the first time in the National squad in 2007. He made his first appearance with the national in a home game for the Euro 2008 qualifiers against Malta.
After four years in Super League and Panionios the time had come for the big step which would change his career for ever. So
in January 2008 the greek manager made his transfer to Panathinaikos, although Olympiacos has shown great interest for his acquisition.Panathinaikos acquired the player paying 2 million Euros to Panionios and 1,8 to the player for a 4 years contract.
This partnership lasted until 2009.