Crafting a hero image is a critical strategy for green brands to fulfill environmental responsibilities and gain external recognition. How can the two types of heroic figures—a guardian and a leader—better inspire consumers’ advocacy for green brands? And what are the differences in consumers’ perceptions of these two distinct heroic figures? Through 4 scenario-based experiments and 2 natural scene quasi-experiments, this paper explores the dual mechanisms and boundary conditions of the impact of the Guardian Hero Image (GHI) and the Leader Hero Image (LHI) on green brand advocacy. The results show that brand admiration and moral need satisfaction serve as dual mediators between green brand hero images and green brand advocacy. Compared to LHI, GHI significantly enhances consumers’ brand admiration; conversely, LHI better satisfies consumers’ moral needs compared to GHI. Additionally, this paper further investigates the moderating effects of consumers’ perceived resource availability and green brand typicality. The study advances the theoretical understanding of brand hero images and provides managerial implications for the strategic design of hero images in green branding.