The PeeR Investigators Mentoring Experiences in Research (PRIMER) program was developed to enhance mentorship and support in Course-based Undergraduate Research Experiences (CUREs) at our institution. This program leverages PRIMER's prior research experience in computational biology courses to mentor students in our bioinformatics-focused CUREs. PRIMERs guide students through research projects and provide tailored support in technical research tasks and scientific writing. They also provide mentoring to students through the research process and help them navigate the next steps in seeking out additional research experiences. PRIMERs, who consist of current undergraduates and recent graduates of our program, undergo training on engaging students in research, peer mentoring, and providing constructive feedback on written assignments. This study reports on the first iteration of the PRIMER program, evaluating its design and impact on the professional development of PRIMERs through focus groups and its effectiveness within our CUREs through student surveys. Findings indicate that PRIMERs developed valuable transferable skills, particularly in scientific communication, providing feedback, and peer mentoring. Students involved in the CUREs aligned with the PRIMER program reported that PRIMERs played an integral role in enhancing their learning experience, offering research support, and fostering a positive research environment.