The Constitutional Era is one of the most important periods in contemporary Iranian history, in which an attempt was made to establish a new link between Iranian historical traditions, Islamic values, and new legal requirements. This research aims to review the manifestations of Iranian-Islamic identity in the legal thought and discourse of this period and examines how this identity is reflected in constitutional legal texts and debates. The main hypothesis is that the constitutional legal discourse was not based on the opposition of Iranianness and Islamicness, but on their integration and the formation of concepts such as legalism and justice. The research method is descriptive-analytical and based on historical documents, laws, political-legal treatises, and the press of the Constitutional Era. The findings of this paper show that Iranian-Islamic identity in this discourse was a basis for legitimizing the new legal and political order, and the weakness in its institutionalization is considered one of the main challenges of this period. As a result, rereading this intellectual heritage can be effective in understanding the roots of national identity and confronting the cultural and legal issues of today's Iran.