Interns possess a unique career status, straddling a career boundary between intern student and regular employee. Taking into account interns' ambiguous and often precarious career status, this study investigates the factors that shape an intern's perceptions of himself or herself as an organizational insider, and how this perception in turn determines his or her transition from intern to employee within the host organization. To address this question, the current study collected data at three time intervals, from 303 intern-supervisor dyads. The findings indicate that an intern's perceived insider status was predicted by both task significance and participative leadership experienced during their internship, and ultimately insider status mediated an intern's transition to regular employment with the host organization. The findings provide important insights into at a pivotal career juncture, given internships are fast becoming a preferred career entry point into a range of postuniversity vocations.