We present a case study of a multi-year, academic civic engagement (ACE) collaboration in a computer science capstone course. ACE projects in computer science provide an avenue for students to apply software development concepts to real-world projects with actual clients, and can offer meaningful engagement with ethical issues. The typical time-limited nature of ACE projects within a single course leaves little time for reflection, iterative development, maintenance, and evolution of priorities, centering student learning outcomes over community partner goals. The model presented here is sustainable and robust to changes in personnel on both the community side and the academic side, including student participants. We highlight the importance of an involved center for civic engagement to facilitate relationship formation and frame civic learning for students. We address how longevity facilitates a true iterative and collaborative development process, supports the development of trust relationships, and opens up space for transformational change.