In the age of growing global populism, the continued popularity and relevance of a populist government is anchored on the ability of its populist leader to convince the voters that the primary objective of his foreign policies is to secure the interests of the state and its citizens. However, without an adequate level of state power, pursuing realist foreign policies to improve the state’s relative gains and position in the international system can pose significant risks even for the most influential populist leader. Hence, the question is, how do populist leaders acquire an adequate level of state power to implement realist foreign policies, without ultimately losing their political capital and institutional legitimacy in the process? To answer this question, I develop a model that illustrates the three-way linkage between populism, securitization, and realism. I use this model to explain the rationale behind President Donald Trump’s `America First’ doctrine, as well as its implications for U.S. foreign policy making. I argue that ``populist securitization’’ is a conduit through which populist leaders formulate, execute, and justify their realist foreign policies. Using Trump’s securitization of the U.S. economy as a case study, I reveal how a populist securitization act can trigger the illiberal tendencies and nativist sentiments of the nationalistic voters, which, in turn, allow populist leaders to maintain their popularity and legitimacy among these voters while they experiment with realist foreign policies.