This work describes the implementation of a hierarchical team model, the Integrated Peer Leadership Program (IPLP), in a calculus-based college introductory physics classroom. Using this model, in which students in the course engage with their peers throughout the semester, we observe a significant increase in the students' likelihood of successfully completing the course. The model also reduces the gap between underrepresented minority (URM) and non-URM students. Learning gains using the IPLP format are improved as compared to previous data for traditional classes. The model transforms a traditional lecture style class into a student-centered class without additional time requirement or cost to the instructor or institution, and we anticipate that it will be portable to other large section introductory college science courses.