Corporate political activity (CPA) research has traditionally focused on instrumental and strategic value, explicitly ignoring how external stakeholders, specifically the public, view the legitimacy implications of CPA, in particular with regard to partisan forms of CPA. Yet, recent research has begun introducing normative considerations into CPA, highlighting the impact of public evaluations on CPA, and partisan CPA, in particular. Focusing on normative affective legitimacy, as proxied by the tone of mass-media reporting rhetoric, this study explores the effect of firm and CEO partisan political contributions on corporate affective legitimacy. Utilizing three types of dynamic panel data analyses on S&P 500 firms over 20 years, the study provides consistent evidence that both firm-level and CEO-level partisan political action committee contributions are negatively associated with affective-based corporate legitimacy. Post hoc analyses reveal that in response to affective-legitimacy evaluations, firms reduce firm-level partisan political contributions and lobbying expenditures, but not other forms of CPA or partisan CPA. The study also finds that state-level public political polarization moderates the association between CEO partisan contributions and firms’ affective-legitimacy evaluations. This study is the first to systematically document the negative normative impact of CPA and partisan CPA. It strongly informs CPA theory and has practical implications for executives’ use of partisan CPA.