Background: The mentoring and leader–member exchange (LMX) literature suggests that the relationship formed between interns and their supervisors contributes to interns’ career development. Although interns and their supervisors evaluate their relationship quality differently, the quality of intern–supervisor relationship is often evaluated only by interns in the literature. Purpose: This study examined college intern-supervisor relationships from both the intern and supervisor perspectives. Methodology/Approach: The quantitative data were collected from 183 college intern-supervisor pairs in the United States by a survey questionnaire. Interns and supervisors both reported their weekly interaction frequency and their LMX quality. Interns also reported their perceived career support received from the supervisors and clarity of their professional identity. Findings/Conclusions: For both interns and supervisors, their interaction frequency was positively related to their evaluation of LMX quality. However, only interns’ perceived LMX led to a greater perception of career support, which in turn fostered a greater sense of clarity of professional identity among interns. Implications: The study highlights the importance of interaction frequency in the development of high-quality intern–supervisor relationships and intern–supervisor differences in evaluating the relationship. Guiding both interns and supervisors to develop relationships can benefit interns’ professional growth and better address employers’ recruitment needs through college internship programs.