Studies have identified gaps in the development of undergraduate students in science, technology, engineering, and mathematics (STEM). Students lack communication and problem-solving, impeding employment opportunities post-graduation. It is essential to prepare students for employment in STEM fields, as these fields remain in high demand and offer competitive wages for economic stability. Research has revealed that students gain critical thinking and problem-solving skills through students mentoring experiences. Evidence surrounding the inclusion of active learning strategies for in-classroom pedagogy has expanded in recent years, but the support mechanisms beyond the classroom remain unclear. Herein, we followed students for a decade after participation in our mentoring pre-professional training program, Nebraska STEM for You (NE STEM 4U). This phenomenological study utilized interviewing techniques and descriptive statistics to demonstrate how a midsized, metropolitan university STEM mentoring program supported the development of NE STEM 4U participants. We found that engagement in an after-school mentoring program provided participants with a model of mentorship. Participants also developed transferable professional and personal skill sets, including communication, perspectives, conflict resolution, and professional development. (author abstract)