This dissertation addresses two related questions: what does attention to philanthropy reveal about Christianity in the postwar United States, and how does consideration of religion reorient stories about modern, organized giving? To do so, it analyzes the most concentrated and sustained external source of financial provision for postwar Christian communities, Lilly Endowment, Inc. Over fifty years, Lilly Endowment's engagements with American Christians—and the reactions of its critics—illuminated the assumptions underlying much contemporary philanthropic practice. Leaders at the Endowment preferred local projects, often embracing relationships over rationalism and stability rather than rupture. Most importantly, they believed the nation's wealthy had a responsibility to bankroll its faithful. These features set the foundation apart from many of its more famous counterparts. That distinctiveness revealed a great deal. Because most U.S. foundations rejected religious projects, the decisions of figures at Lilly Endowment could exert outsized influence over midcentury Christianity. This dissertation thus joins perennial debates regarding the role of private money in American public life. To varying degrees, the movements that appear in the following pages—Christian college reform efforts, grassroots lay renewal initiatives, alternative seminary models, international humanitarian ventures, and elite research teams—all strove for independence. Yet over and over, experience curbed their idealism, and they were forced to negotiate questions of power and interdependence as they cultivated external donors: the story of postwar American religion is, to some degree, a story of which religion managed to win funding. By the 1980s, however, the waning of the Endowment's uniqueness proved the power of prevailing philanthropic models—the foundation's greatest public success occurred at the moment that it most replicated the techniques and practices of its philanthropic peers. The dissertation concludes with a reflection on the future of religious philanthropy in a moment of growing fortunes and diminishing religious observance.