Public universities are intent on increasing degree completion for many reasons. A stronger policy focus on completion and interest in removing students' financial hurdles has led to a rapid proliferation of completion grant programs. This paper reports on a mixed-method implementation study of completion grant programs at seven broad- and open-access universities. Drawing on case studies of completion grant programs and student surveys, we examine the work of the administrators and professionals who create and implement these programs. As it can diminish program efficacy and increase inequality, we pay particular attention to administrative burden for staff and students. We consider how the implementation of completion grant programs vary and how these variations are associated with administrative burden. We also analyze the drivers of variation in that administrative burden, and describe model elements for administering completion grants that aim to minimize administrative burden and maximize efficacy. [For the corresponding grantee submission, see ED610450.]