Past research suggested that pre-college experiences contribute to first-generation (FG) students’ belonging concerns during their transition to college. Results from an archival longitudinal survey study of freshman science majors (N = 546) revealed that variability in on-campus experiences during the first semester, in particular, perceived science faculty support, predicted changes in the sense of belonging in the first semester. This relationship was especially stronger for FG students. Additionally, the sense of belonging measured at the first semester further significantly predicted student persistence in science at the end of sophomore year, controlling for students’ expected faculty support and belonging to science measured at the beginning of their college. The findings suggest that creating an environment where incoming students can easily perceive their science faculty’s intention to care and support students might be beneficial to reduce FG students’ belonging concerns and support their pursuits in science.