Pro bono has undergone a profound transformation. Whereas for most of American legal history, pro bono was ad hoc and individualized, dispensed informally as professional charity, within the last twenty-five years it has become centralized and streamlined, distributed through an elaborate institutional structure by private lawyers acting out of professional duty. Pro bono has thus emerged as the dominant means of dispensing free representation to poor and underserved clients, eclipsing state-sponsored legal services and other nongovernmental mechanisms in importance. This Article examines the causes, features, and consequences of pro bono’s institutionalization. It begins with . an analysis of the forces behind pro bono’s institutional rise, emphasizing the role of the organized bar, federal legal services, the nonprofit sector, and big law firms. This Article then maps the contours of pro bono’s institutional architecture, analyzing the structures of organizational collaboration, mechanisms of efficiency, strategies for accountability, and processes of adaptation that define pro bono’s operational identity. It concludes by probing the systemic consequences of pro bono’s new institutional centrality, weighing the pragmatic benefits of leveraged law firm resources against the limitations imposed by the dependence on private lawyers beholden to commercial client interests.