Limited research has been conducted to explore the mechanisms through which employee involvement affects organizational performance. This article furthers the research on the mechanisms by testing a new causal model based on the theoretical framework of high-involvement work systems. Based on data collected from a sample of civil servants in China, we used structural equation modeling to find that the direct effect of involvement practices on organizational performance is positive and statistically significant. However, the indirect path mediated by job satisfaction and organizational commitment are not statistically significant. In addition, we found that public service motivation exerts a positive and direct effect on organizational performance. PSM is more prominent than job commitment or satisfaction in motivating public employees to work towards organizational goals and to work harder.