The traditional rulers in Nigeria and customary forums such as Jirgas in Pakistan function as hybrid governance institutions that mediate between state authority, local communities, and constitutional norms, asking how they sustain legitimacy and accountability in fragile democracies while delivering justice and managing conflict. The research uses a comparative qualitative approach that analyses policy documents, judicial rulings, and institutional reports (2015-2025), within the frameworks of legal pluralism as constitutional architecture, subsidiarity as a circuit rule, and the state-in-society perspective. The study finds that both countries exhibit functional equivalence but divergent trajectories; Nigeria advances adaptive decentralisation through Alternative Dispute Resolution centers and statutory oversight, while Pakistan consolidated codified integration through the Federally Administered Tribal Agencies’ (FATA) merger and provincial legislation. This shows that sustainable legitimacy in hybrid systems depends on four policy variables: institutionalised interfaces linking local rulings to appellate review, documentation and traceability, inclusion of women and youth, and vertical accountability through judicial and administrative oversight. Thus, hybrid governance enhances democratic resilience only when cultural authority is disciplined by constitutional safeguards, transforming customary legitimacy into a renewable source of participatory statecraft rather than a residual form of informal power.