Globalization, rankings, and the decrease of public funding have created a highly competitive environment for public universities. Internal and external stakeholders increasingly demand better results in term of research, teaching, knowledge transfer, employability, and community outreach. In this new landscape, intangible assets such as reputation and legitimacy are key factors for gaining a sustained competitive advantage. And yet, here remains a lack of clarity about these variables and their relationships. This research aims to increase our understanding of the field by measuring how reputation, by way of its influence on legitimacy, can create a sustained competitive advantage for public universities. We measure reputation and legitimacy by surveying 509 professors from 47 different Spanish universities, considering pragmatic, moral and cognitive legitimacy types and analyze reputation in terms of performance, innovation, citizenship, services, governance, and workplace climate. According to faculty members, a university's reputation has a significative and positive effect on its legitimacy.