Background: Despite an extensive literature-base documenting strong outcomes for undergraduates engaged in service learning, few studies have investigated whether, and to what degree, these outcomes extend beyond the semester(s) undergraduates are actually engaged in service learning. Purpose: This study addresses this gap by following up with undergraduates who participated in an innovative service-learning project as part of their teacher preparation program. Our goal was to investigate the impact their participation has on their practice as teachers of mathematics (postgraduation). Methodology/Approach: Project participants (PPs) and matched controls (MCs) were surveyed using Qualtrics, a web-based survey tool. Both quantitative and qualitative data were collected and analyzed. Findings/Conclusions: Results indicate robust differences between PPs and the MCs self-reported descriptions of their current classroom practices, with the data confirming that participation in reimagined service learning has the potential to affect undergraduates' beliefs, practices, and global mindsets postgraduation--while employed as classroom teachers of mathematics. Implications: Findings suggest that engagement in innovative service-learning projects, as part of undergraduate teacher preparation programs, has the potential to help early career teachers: transform their ideas about teaching and learning, move beyond traditional ideas of what mathematics looks like, and to embrace reform-based instructional methods.