Though the Porter win-win hypothesis has dominated the extant research in the green field, the results of previous studies have been mixed. Many studies have also used the construct of slack to explore how it affects a firm's innovation/performance. Even so, only a vague relationship has been drawn between a firm's slack and its corporate "greening." Drawing on green innovation literature, institutional theory, and firm slack from a resource-based view, we argue that two antecedents (i.e., institutional pressure and the firm's green slack) positively influence companies' propensity to engage in green product innovation (GPI) and improve their results (e.g., green new product success, aka GNPS). In particular, this research empirically investigates the indirect relationship between institutional pressure and GPI through the firm's green slack. This study also tests the mediating role of GPI in the relationship between the two antecedents and GNPS. We test our proposed model using a sample of 170 Taiwanese high-tech firms, including both electrical and electronics manufacturers. The results of structural equation modeling analysis provide support for all direct and indirect hypotheses. This study also provides theoretical conclusions and implications for research and practice.