The relationship between knowledge sharing and organizational performance for high technology start-up companies is not well understood. Using game theory and the concept of competitive advantage through human resource management, I examine employee perceptions of the employment game relating to cooperative knowledge behavior and firm performance as an entry point into researching organizational knowledge utilization. I draw upon classical game theory to develop four measures of perceptions critical to game playing and apply these to organizational situations via a survey instrument. I propose that perceptions of the employment game held by organization members are determinants of cooperative knowledge sharing and subsequently firm performance. I analyze survey data gathered from high-tech workers using both regression and path analysis techniques. The results from this study offer new insights into methods for measuring both the connections between knowledge work and firm performance and the perceptions critical for fostering collaborative knowledge work in high tech firms. Results of the study show a significant relationship between the game theory construct of reciprocity, knowledge building behavior and firm performance. The mediation model was weakly supported but shows potential usefulness for further research in the field of strategic human resource management.