Muslim communities in Lebanon have developed radically new institutions of religious leadership since the advent of the confessional state. These leaderships were created or refined over the course of Lebanon’s first five decades (1920s–1970s), often building on pre-existing institutional norms but shaped by common patterns of integration into a state-centric system of confessional representation. Such institutions have played a key role in representing and reinforcing the sectarianisation of Islam in the country. On the other hand, their proximity to the state has made them prominent advocates of peaceful coexistence and political participation. This paper shows (1) how three Islamic religious leaderships have become institutional expressions of a distinctive Lebanese sectarianism, and (2) how they have in the process become defenders of the nation-state. Focusing on the Sunni office of mufti, this leadership is surveyed alongside its Shi‘i and Druze counterparts to highlight their convergence on a single institutional model. These developments began in response to a French colonial demand for interlocutors with religious communities, and gained urgency as these interlocutors negotiated communal autonomy in religious affairs. The project of communal self-governance – which included jurisdiction over personal status law – called for centralized religious institutions that could manage nationwide bureaucracies. Thus a Sunni mufti, Shi‘i sheikh, and Druze sheikh al-‘aql were each elevated to leadership of new religious hierarchies. While competition among these three leaderships played a part in their development, this paper uses the history of the 1975–90 civil war to show how their common enculturation into the life of the state has generated a strong centripetal tendency in their political behavior.