This paper focuses on the journalistic writings of Teodor Kasap, a Greek Ottoman journalist whose publications dominated the press of Istanbul in five languages from 1870 through 1877, when he was forced into exile. It offers an overview of Kasap’s contribution to the emergence of a culture of public dissent in the decades that followed the Crimean War, and argues for Kasap’s pivotal role in creating the secular and pluralist public culture that grounded the Young Ottoman constitutional movement. From the founding of his first journal, Diyojen, in 1870, through his arrest in 1877 on charges of violating the Ottoman press law with the publication of a cartoon satirizing press censorship, Teodor Kasap was one of the most prominent figures in Istanbul public life. The cultural unification he championed was an important precursor to the demand for a constitutional regime. This paper surveys the rhetorical strategies deployed by Kasap and his collaborators to unite their linguistically and religiously diverse readership and build a sense of common cultural belonging. Kasap’s journals, published in Turkish, Armenian, and Bulgarian as well as French and Greek, collectively transformed Ottoman press culture by expanding it to make room for a new social category: worldly, patriotic, both Muslim and Christian, and steeped in the popular culture of Ottoman Istanbul. By highlighting several episodes in which Kasap intervened in political and cultural disputes, I aim to draw out the substance of his newly invented national persona and sketch its impact on Ottoman public discourse. Kasap’s journalistic ethos combined an unmistakably cosmopolitan outlook with a pointed resistance to both the Tanzimat-era state’s vision and that of European elites. It celebrated the diversity of the Ottoman capital’s working class and the richness of Ottoman folk culture, a tradition that it insisted was shared by Muslim and non-Muslim subjects alike. Above all, it recast imperial subjects as citizens: members of a coherent body politic that stood apart from, and even in opposition to, their government. The efforts of this Turcophone Greek Orthodox journalist to expand and unite Istanbul’s reading public were central to the Young Ottoman project of building a new foundation for Ottoman politics.