The Sadrist movement is widely regarded as one of the most influential political and social forces shaping contemporary Iraq. Led by Muqtada al-Sadr, this movement has gained substantial support among various segments of Iraqi society, particularly the lower and middle classes. Given its significance in Iraq’s political transformations and its relationship with the Islamic Republic of Iran, this article seeks to answer the following question: What are the main contexts and factors underlying the influence and popularity of the Sadrist movement in Iraq? Using a qualitative, descriptive–analytical documentary method, the study develops an analytical model based on four key dimensions: resource mobilization, social identity, populism, and legitimacy. The central hypothesis is that the influence and popularity of the Sadrist movement cannot be adequately explained by a single religious, social, political, or personal factor. Rather, it is the product of a complex and multilayered interaction among interconnected elements. In this framework, religious factors—such as the symbolic legacy of the Sadr family, emphasis on social justice, and the use of religious symbolism—interact with Muqtada al-Sadr’s personal attributes, including charisma and emotional mobilization capacity, as well as his engagement with social and political networks. The convergence of these factors has played a decisive role in sustaining and expanding the movement’s popularity within Iraq’s dynamic political and social landscape.