Undergraduate research experiences offer a range of positive academic and affective student outcomes. However, these benefits often do not reach all students, as research experiences are often selective, favor high-achieving students, focus on STEM fields, and typically target students in their third or fourth year of undergraduate studies. To address this issue, the University of Maine implemented the Research Learning Experiences (RLEs), a series of semester-long course-based research experiences in conjunction with pre-semester bridge experiences that are open and accessible to all incoming first-year students. The RLE courses spanned STEM and non-STEM disciplines while focusing on research and academic exploration as well as social engagement. Pre- and post-surveys from RLE participants (n = 153) and a comparison group (n = 159) demonstrate several positive student outcomes. We found that RLE students reported a greater sense of belonging to their course, belonging to the university, and research identity compared to their peers, regardless of discipline. These outcomes were largely consistent across student demographics. For all students, greater belonging (university and course) was positively associated with first-year retention, highlighting the importance of designing undergraduate research experiences that incorporate social connections and cohort-building in the first semester. These results contribute to our understanding of course-based research experiences undertaken by students from an array of majors and backgrounds, specifically, that they can produce positive outcomes in both STEM and non-STEM majors. This program can serve as a model for institutions aiming to broaden participation in undergraduate research across disciplines, particularly in the first semester.