Doctoral student creativity is critical for technological innovation and knowledge production. Based on the extended scientific and technical human capital (STHC) theory, a moderated mediation model was constructed to explore how supportive supervision is associated with doctoral student creativity through the simultaneous mediating effects of academic buoyancy and network ties and the moderating role of family support. A sample of 637 doctoral students from China participated in this study. In particular, the findings suggest that supportive supervision is positively related to doctoral student creativity through the simultaneous indirect effects of both academic buoyancy and network ties, while the mediating effect of academic buoyancy is stronger than that of network ties. Moreover, the significant moderation effect of family support on the relationship between network ties, academic buoyancy, and creativity reveals that students with greater family support are more likely to benefit from the academic buoyancy while leading the mediating effect of network ties to be dispensable, implying that family support can be a double-edged sword. The findings provide implications for supervision that can improve doctoral student creativity by attaching importance to social capital and psychological capital while considering the nuanced influence that family support may exert.