This paper examines the ways in which academically vulnerable students benefit from non-academic support. By reviewing theories of student persistence as well as program evaluation literature, the author identifies four mechanisms by which non-academic supports can improve student outcomes, including persistence and degree attainment. Programs associated with positive student outcomes seem to involve one or more of the following mechanisms: (1) creating social relationships, (2) clarifying aspirations and enhancing commitment, (3) developing college know-how, and (4) making college life feasible. Identifying these mechanisms allows for a deeper understanding of both the functioning of promising interventions and the conditions that may lead students to become integrated into college life. Notably, each of these mechanisms can occur within a variety of programs, structures, or even informal interactions. The paper concludes by discussing avenues for further research and immediate implications for colleges. A tabular review of empirical studies is appended. (Contains 4 footnotes and 1 table.)