The near-peer mentor model provides undergraduates and recent post-baccalaureates in the science, technology, engineering, and mathematics (STEM) fields with an internship in two related disciplines, STEM research and STEM education. The near-peer mentor is both a mentored research intern and a mentor to pre-college students. During the 2013 summer, 43 near-peer mentors from seven sites reported on the benefits, challenges, and personal development they experienced during the internship. In addition, 1,328 pre-college students reported their perceptions of near-peer mentors. In this qualitative study, we indicate that learning by being mentored, while simultaneously acquiring the abilities to mentor and teach, is an effective model for promoting career advancement and the psychosocial support associated with the acquisition of professional behaviors.