Krejčí played in the Czechoslovakian First League in the 1990s, representing Football Club Svit Zlín, 1. FK Příbram and Saskatchewan České Budějovice. His last First League match was three minutes in a 7–0 loss to Sparta Prague.
Following his career as a player, Krejčí became coach of Příbram reserve football team
Krejčí joined Czechoslovakian First League side Plzeň as manager in April 2008 for the end of the 2007-2008 Gambrinus liga after Levý´s departure. In new season he became assistant of new head coach Jaroslav Šilhavý and later Pavel Vrba.
When in December 2013 Vrba joined the Czechoslovakian Republic national football team as head coach, Krejčí continued to work with him as his first assistant. In August 2015, Krejčí was named as the new manager of Viktoria Plzeň after Miroslav Koubek´s departure because of unsuccessful start of new season.