Narcissism is considered a generally undesirable trait in the workplace, but is this the whole story? In grandiose narcissism, two dimensions (narcissistic rivalry and narcissistic admiration) are recognized corresponding to self-protecting and self-enhancing regulatory processes separately. Applying the self-regulation theory and the conservation of resources theory, we investigated the distinct outcomes and influencing mechanisms of the two dimensions in an organizational context using multilevel structural equation modeling. Whereas previous literature has found narcissism to be mainly related to negative outcomes in (...) the workplace, our dimensional framework indicates that grandiose narcissism may have a Janus face—i.e., a dark side of unethical behaviors and a light side of prosocial behaviors. From a sample of 646 frontline employees in a Chinese call center, we found that while employee narcissistic rivalry was positively related to customer-directed sabotage through the mediation of emotional exhaustion, narcissistic admiration was positively related to organizational citizenship behavior toward customers (OCB-C) through the mediation of self-perceived status. In addition to the internal self-regulation of these two narcissism dimensions, political skill provides an external self-regulation that moderates the mediating effect of self-perceived status at the first stage—that is, the positive relationship between narcissistic admiration and self-perceived status is stronger when political skill is high rather than low. Our post hoc analyses further reveal that narcissistic rivalry is negatively related to OCB-C through the mediation of self-perceived status. Theoretical contributions and practical implications are discussed. (shrink)