The objective of this research is to analyze the mediating role of Green Supply Chain Management (GSCM) in the main Green Intellectual Capital (GIC) and Sustainable Performance (SP) relationship, as well as the moderating role of Green Agriculture (GA) in the GSCM–SP relationship. To achieve this objective, a theoretical model is proposed based on the literature review and then analyzed using structural equation modeling (PLS-SEM) based on a sample of 196 Spanish wineries collected from September 2022 to January 2023. The results reveal that while GSCM partially mediates the GIC–SP relationship, GA positively but not significantly moderates the GSCM–SP relationship. To the best of our knowledge, there are no previous studies that have contextualized the model proposed in the wine industry, so the study represents the generation of new knowledge about the meaning of the relationships presented. Furthermore, no previous research has analyzed the moderating role of GA in the GSCM–SP relationship, so the study advances understanding of the variables that may affect this link (GSCM–SP).