The few extant studies of Jesuit martyr and theologian Yves de Montcheuil focus on his life and theology. This article combines these considerations with philosophical and political ones by examining how Montcheuil’s spiritual resistance to Nazism emerges from his study of action and justice in the thought of Nicolas Malebranche and Maurice Blondel. Montcheuil’s oeuvre culminates in a lived theology of sacrifice, and shows how the French war experience contributed to doctrinal development in areas such as faith and action, liberation theology, church—state relations, and lay ecclesiology.