Abstract Purpose This study examined the impact of socioeconomic status (SES) on medical education in the context of person-environment fit (PE fit) theory, and specifically focused on the medical school experiences of students from lower-SES backgrounds. Method A constructivist approach was used in this qualitative study of 48 medical students from 27 US medical schools, all of whom self-identified as first-generation college graduates and/or being from a lower-income background (30 were both). Semi-structured audio-only interviews were conducted with these demographically and geographically diverse students from November 2021 through April 2022. Themes were identified using open coding and content analysis software. Results Almost all, 44 of 48, interviews included themes related to PE fit. Medical students indicated three interacting domains in which PE fit is relevant for them: (1) school, (2) clinical, and (3) professional environments. Learners from lower-SES backgrounds describe struggling to navigate multiple environments that are unfamiliar, culturally complex, and both personally and financially costly. They also describe ways they are addressing gaps, generating positive changes, supporting underserved patients, and broadening the perspectives of peers and educators. Conclusions PE fit theory provides a lens to understand unique aspects of lower-SES medical student experiences, including navigation of professional identity formation. It is critical for medical schools, funders, peers, and professional communities to sustain learning environments that support the flourishing of medical students from lower-SES backgrounds. This support includes transferring the burden of addressing fit from individual learners and marginalized classes of learners to educational, clinical, and professional organizations.