World War I significantly impacted U.S. society and politics long before the United States officially entered into the war's frontlines in 1917. Even as historians have begun to pay closer attention to this process, they have until now largely failed to notice a particular group of colorful and highly emblematic public elite actors: charitable foundation philanthropists. With the soon-to-be globally active Rockefeller Foundation a cohort of ambitious U.S. progressives and social engineers—later ardent supporters of global science funding during the interwar years and beyond—utilized their war experiences to shape the wartime philanthropic agenda. This article focuses on the Foundation officers’ profiles and the beginnings of their more concerted engagements during World War I in order to show how, in their mindsets and tactics, Rockefeller philanthropists disregarded American neutrality. From the outbreak of the war in 1914, they mobilized themselves to the point of pleading for and entering into direct commitments at home and abroad, especially in the European war zone. With the official entry of the United States into war in early April 1917, Rockefeller officials and collaborators became openly “combat” philanthropists, resolutely assisting the moral stabilization efforts of the U.S. military and conducting support campaigns to bolster, most notably, the American alliance with France. The incubation and infancy period of Rockefeller philanthropy as a subsequently ubiquitous phenomenon of the American twentieth century is inseparable from the impact of the Great War.