Legitimacy has been used to understand institutional and faculty behaviors within higher education contexts. Faculty members frequently apply the concept of professional legitimacy to their work, such as publishing and teaching. Few studies have considered how legitimacy is enacted when advising undergraduate students about graduate education. Through in-depth interviews with 50 faculty members, our findings illustrate that faculty members enact professional legitimacy in endorsing students by opening their own social networks; redirecting students away from graduate education, and demonstrating how to perform, or think and act like an aspiring academic. Implications for practice and future research conclude the article.