Kruys played his entire career for FC Utrecht (1978–1988), 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.
Kruys played exclusively for FC Utrecht (1978–1988), with a brief interlude at RKC Waalwijk in 1987. He then concluded his playing career in 1988 and shifted to coaching, managing several clubs including AGOVV Apeldoorn, Cambuur Leeuwarden, FC Den Bosch, De Graafschap, FC Dordrecht, and FC Volendam.