The church is missionary by nature. But what about public church mission in secular societies? Furious religion mobilizing against rebarbative secularity? Withdrawal to seek exemplary perfection? To the contrary, theologically principled consultation with the sociology of J. Casanova on deprivatized religion leads to public witness in modern societies. Public theology can interpret deprivatized religion as an expression of prophetic and kingly elements in church mission. However, sociology leaves the priestly element as if private. What might ecclesiology, missiology, and public theology say about a public aspect of the priestly element in the church’s witness in modern societies?