Previous research has shown that public and nonprofit managers enhance their organization’s performance through external networking. However, compared to the extensive literature dedicated to the positive effects of managerial networking on organizational outcomes, little is known about whether and how networking affects the managers themselves. Against this background, our study investigates individual-level consequences of managerial networking. Drawing from the job demands-resources model, conservation of resources theory, and social capital theory, we propose that external networking may be a double-edged sword for managers. Results from a survey among 129 managing directors of the German Red Cross suggest that managers with the ability to develop external networks are motivated by the support they perceive from external actors and therefore show higher levels of job performance. Simultaneously, our findings indicate that building extensive external networks may be a costly activity. More precisely, we found that external interactions deplete managers’ energetic resources, which leads to higher levels of emotional exhaustion. Aside from these psychological processes, we identified a purely instrumental process that operates in parallel. Accordingly, managers with networking ability gain access to resources, which pays dividends for their job performance. Based on these findings, we derive implications for both networking theory and management practice.