In this paper, we investigate the effect of participating as a near-peer mentor for computing activities in undergraduate courses across disciplines. Many studies on near-peer mentorship have demonstrated benefits to the academic, professional, and self-efficacy growth of mentees. While we acknowledge the mutual benefits of the program on mentees and mentors, we focus on how participation as a mentor in an undergraduate Computing Fellows program contributes to the strengthening and expansion of the mentors’ computing identity through their interactions in the program. The Computing Fellows program “attaches” near-peer mentors to undergraduate courses across the sciences, humanities, and arts creating an interdisciplinary learning environment for the fellows and the students. The mentors support the integration of computing into courses through activities including in-class workshops and drop-in office hours. In a mixed-methods study, we conducted semi-structured interviews over two years with mentors identifying as women, after their participation, and we cross-reference the results with student evaluations from the courses. We find that fellows’ experience in the program, both as near-peer mentors and through their engagement in critical discussions about computing and computing pedagogy as part of their training, expands and deepens their computing identity and the various ways they can engage with computing in their lives in and beyond college.