The study explored the experiences of undergraduate students during a semester-long, leadership development internship course offered at a large research university in the southern United States. The researchers employed qualitative content analysis to examine sixty-five student internship portfolios and identify the leadership capabilities that students applied and/or developed as part of the internship. Students identified self-awareness, growth, project planning, team management, and adversity management as the main leadership capabilities used during their internship experience. Results also indicated that students expanded their concept of leadership and built leadership self-efficacy. The study provides preliminary support for including a leadership internship within the curriculum to support student leadership development.