In the past decade, family supportive supervisor behavior (FSSB) has emerged as an important factor that can help employees manage work–family needs. Although the existing literature has documented the benefits of FSSB, we know little about the emerging process of FSSB. Drawing on the conservation of resources theory, we propose that supervisor engagement in FSSB is influenced by the extent to which the supervisor has sufficient resources for work. This study uses the joint effect of supervisors’ family–work conflict (FWC) and organizational work–family culture to predict the time supervisors spend on core tasks, FSSB, and subordinates’ work–family conflict (WFC), in sequence. Data were collected from paired supervisor–subordinate dyads among 83 supervisors and 276 subordinates. The results indicate that supervisors with high FWC spend more time on core tasks and display less FSSB, which ultimately result in higher subordinates’ WFC, especially in organizations with a lower level of organizational work–family culture. In contrast, supervisors’ FWC does not result in any negative influences on the supervisors themselves or their subordinates at work in organizations with a higher level of organizational work–family culture. Therefore, the theoretical model provides evidence that supervisors’ negative work–family experience cascades down to their subordinates.