How do personality-based ethical orientations shape individuals’ sense of purpose and their intentions to engage in prosocial venture creation? Drawing on Social Cognitive Career Theory (SCCT), this study examines the moral and psychological foundations of social entrepreneurial intention — a prosocial behavioral intention — using data from 29 countries (N = 8003). We test how two contrasting sets of personality traits, the Light Triad (faith in humanity, humanism, Kantianism) and the Dark Triad (Machiavellianism, psychopathy, narcissism), influence individuals’ sense of life purpose and, in turn, their intention to engage in social entrepreneurship. Results show that Light Triad traits enhance life purpose and foster stronger social entrepreneurial intentions, whereas Dark Triad traits reduce life purpose and weaken such intentions. Narcissistic women, however, report higher social entrepreneurial intentions than men. By identifying personality- and purpose-based antecedents of a prosocial behavioral intention — long a central object of inquiry in environmental psychology as a precursor of sustainable behavior — these findings advance the psychology of moral engagement and offer implications for how virtue and vice translate into prosocial action in organizational and societal contexts.