Familial and organizational support are important for employees to sustain quality of life and workplace performance. Grounded in the conservation of resources theory, this study explored the underlying mechanism between family member support and employee well-being. Specifically, we examined how the relationship is mediated by psychological capital, and how perceived organizational support amplifies the effect of familial support on psychological capital. Using survey data from 231 Vietnamese employees, results showed that family member support positively predicted employee well-being. This relationship was mediated by psychological capital. Additionally, the relationship between family member support and psychological capital was moderated by perceived organizational support, becoming stronger under conditions of high organizational support. This study offers important theoretical implications regarding the roles of family and organizational support in impacting employee well-being and happiness. Additionally, it provides practical implications for strategic human resource management, highlighting approaches to develop a socially sustainable work environment that promotes employee well-being.