We integrate prior theoretical perspectives on humor to test the processes through which leader humor (LH) facilitates subordinate OCBs. In doing so, we argue that humor is a key interpersonal resource for leaders and derive our comprehensive model with logic from three individual-resource-related theories—social exchange theory, conservation of resources theory, and broaden-and-build theory. Leader-triggered positive emotion and subsequent social exchange, operationalized as LMX, functioned as key sequential mechanisms mediating the relationship between LH and subordinate OCBs. LH induced positive emotion in subordinates which fostered high-quality LMX and, in turn, OCBs. Contrary to our expectation, the stress relief explanation of LH was not supported. The present research contributes to our knowledge of humor in organizations, and particularly LH, as it is the first to establish a link between LH and OCBs and also represents the first integration and concurrent examination of three functions of humor. We additionally offer empirical contributions to the humor literature by providing a comprehensive test of prior conceptual arguments regarding mechanisms of LH and validating a measure of LH that can be used in future research. For LMX research, we draw attention to LH as an overlooked but important socioemotional resource for social exchange.