This article examines the relationship between J.P. Morgan & Co. and France during the First World War. It argues that the dealings between the French government and the partners of J.P. Morgan & Co. from 1914 to 1918 were characterized by personal difficulties between successive French representatives and the partners of J.P. Morgan & Co. Contributing to a strained relationship was the place of Morgan, Harjes, the French affiliate of J.P. Morgan & Co., within the House of Morgan. Herman Harjes, the senior partner in Morgan, Harjes, though a proponent of Franco-American amity, became disenchanted with his New York partners as the war continued. The feeling was shared by those in New York, who reevaluated the role of Morgan, Harjes within the House of Morgan—until the French affiliate's eventual disappearance in 1926. While sympathetic to France, and instrumental in sustaining French credit during the war, the partners of J.P. Morgan & Co. conceived of the Allied cause as the British cause, a perspective that led them to rebuff calls for greater Franco-American financial cooperation.