Gerf Kruys devoted his career as a professional coach of FC Utrecht, RCK Waalwljk, FC Den Bosch, and FC Volendam.
Kruys played his entire career for FC Utrecht (19781988), except for one short spell at RKC Waalwijk (1987). He retired in 1988, and soon afterwards became a coach who worked for AGOVV Apeldoorn, Cambuur Leeuwarden, FC Den Bosch, De Graafschap, FC Dordrecht and FC Volendam. 
