This article uses the early career of Nichifor Crainic (1889–1972) to show why Orthodox Christianity became a central element of Romanian ultra-nationalism during the 1920s. Most Romanian nationalists were atheists prior to the First World War, but state-sponsored nation-building efforts catalyzed by territorial expansion and the incorporation of ethnic and religious minorities allowed individuals such as Crainic to introduce religious nationalism into the public sphere. Examining Crainic's work during the 1920s shows how his nationalism was shaped by mainstream political and ideological currents, including state institutions such as the Royal Foundations of Prince Carol and the Ministry of Cults and of Art. Despite championing “tradition,” Crainic was committed to changing Romanian society so long as that change followed autochthonous Romanian models. State sponsorship allowed Crainic to promote religious nationalism through his periodical Găndirea. Crainic's literary achievements earned him a chair in theology, from which he pioneered new ways of thinking about mysticism as an expression of Romanian culture and as crucial to understanding the Romanian nation.