<p>Charismatic leadership plays a central role in the emergence and early success of many ideal-driven organizations, social movements, and mission-oriented enterprises. Yet these organizations recurrently struggle to combine three normatively desirable objectives over time: a strong shared identity, sustained and influential internal diversity, and long-term organizational sustainability. This paper argues that this difficulty reflects not contingent failures of governance or leadership, but a structural constraint. We propose that organizations grounded in charismatic authority face an organizational trilemma: identity, diversity, and sustainability are pairwise compatible, but cannot be jointly realized beyond non-trivial levels. Charisma can intensify coordination, delay routinization, and symbolically reframe internal tensions, but it cannot remove this underlying incompatibility. The argument is developed through a minimal formal clarification embedded in a broader conceptual analysis grounded in the civil economy literature on ideal-driven organizations. Within this framework, existing results on charismatic leadership—most notably the “founder’s curse” analyzed by Antoci et al. (Commun Nonlinear Sci Numer Simul 84:105190, 2020)—are reinterpreted not as contingent governance pathologies, but as dynamic trajectories within a constrained space of organizational possibilities. The paper’s central implication is normative rather than pessimistic. Organizational fragility often arises not because organizations are poorly governed, but because they are asked to pursue incompatible goods simultaneously. A mature civil economy does not deny this limit, but learns how to govern responsibly within it.</p>