This study explores the influence of Portuguese higher education students’ pro-sustainable orientations in promoting social entrepreneurship when mediated by perceived feasibility and desirability. The sample was collected through a questionnaire of 391 Portuguese higher education students, and the Partial Least Square (PLS) method was applied to a proposed research model. The pro-sustainable orientation of Portuguese higher education students positively influences the social entrepreneurial intention and the perceived desirability of starting an entrepreneurial activity. Furthermore, the pro-sustainable orientation of these students positively affects the social entrepreneurial intention when mediated by the perceived desirability of starting an entrepreneurial activity. The study fills the gap by relating sustainable development, the general theory of entrepreneurship, and the paradigms of social entrepreneurship. Considering the pro-sustainable orientation of entrepreneurs, perceived viability does not significantly affect social entrepreneurial intention, challenging the core assumptions of the theory of planned behavior and the entrepreneurial event model.