This empirical research investigates the transformative impact of crises of faith on altruistic behavior among members of Free Church–Pentecostal congregations in Germany. Based on a mixed-methods design with 100 participants, the study employed standardized scales and qualitative interviews to explore how experiences of religious disillusionment reshape motivations for prosocial action. Findings reveal a strong negative correlation between crisis intensity and religious altruism, and a positive correlation with secular altruism. While faith-stable individuals demonstrate the highest levels of religious engagement, those who permanently leave faith communities develop stronger secular helping motivations, though with slightly reduced overall prosocial activity. Remarkably, participants who resolved their crises by reintegrating into faith contexts exhibited the highest long-term commitment, blending both religious and secular sources of altruism. The study highlights that faith crises, rather than eroding altruistic behavior, often serve as turning points that reconstitute it in new forms relevant to broader social and civic engagement.