Despite significant efforts to broaden participation in postsecondary science, technology, engineering, and math (STEM) education, students from historically minoritized populations continue to face systemic barriers related to access, departmental climate, and institutional practices. Previous research suggests that campus-level STEM diversity programs often serve as a valuable resource for persistence and completion among students from underrepresented populations. However, more knowledge is needed to better understand how students experience STEM diversity programs and identify with their specific practices and activities, how those practices and activities shape students' experiences, and how the practices, activities, and participation influence how students view themselves as members of the STEM community. Increases in the number of underrepresented students completing STEM degrees would result in new innovations to address world problems, more varied representations of scientists, and more individuals who could mentor future generations of learners. This study of 20 underrepresented students, all of whom participated in the Louis Stokes Alliance for Minority Participation (LSAMP) program, describes the programmatic influences of LSAMP that support students' successful progress within STEM disciplines. Data reveal that: (a) students entered the LSAMP program with self-defined strengths; (b) the LSAMP program provided formal academic support; and (c) students experienced evolving forms of scientific and identity development. This study centers students' voices to inform educational practices, policies, and future research focused on the persistent need to broaden participation in STEM careers.