This dissertation investigates the role of religious belief in shaping early twentieth-century American corporate structures and conceptions of the public good. It is centered on the rise and transformation of three prominent American non-profit philanthropic foundations. In examining the precedents set for these institutions by religious benevolence and charitable societies, I offer a new approach to understanding ongoing discussions regarding the history of American philanthropy. Data from three case-study foundations (the Pew Charitable Trusts, the Lilly Endowment, and the Henry R. Luce Foundation) emphasize the role of religious belief in the distribution of different types of influence, the role of the state in securing the welfare of its citizens, and the ways in which non-profit foundations, initially met with dramatic skepticism, became legitimated across American society. I argue that shedding light on the nature of religious belief in “secular” moments reveals insights into the nature of policy formation, the evolution of market structures, and the power of dissent within various religious and global contexts. My project’s insistence on the relevance of religion as both animating force and as critical lens in understanding both secular philanthropy and market rationalities intervenes in the literature on this topic and complicates the secular/religious binary that structures how Americans think about public institutions. In doing so, I make the case for the value of religion in further analyzing how Americans invest faith into tax regimes, market structures, and potential futures.