Designing public policy entails navigating a myriad of intricacies, from managing multiple stakeholders with diverse interests to dealing with incomplete and conflicting information. The challenges inherent in designing effective public policies revolve around the fundamental discrepancy in achieving synergy between the intended functional objectives, the anticipated behavior of social agents, and the actual observed behavior. This misalignment necessitates a meticulous analysis for designing policies within the evolving environment. In response to these challenges, in this paper, we explore the utility of the function–behavior–structure (FBS) construct to design public policy. Through this approach, we establish a conceptual map to address the intricate complexities associated with designing public policy. Our primary objective is to propose a design engineering method that empowers policymakers (and decision-makers) to navigate and overcome the common challenges inherent in designing public policy. By emphasizing the synergy between function, behavior, and structure, we facilitate a strategic analysis of various scenarios and discern the disparities between the actual and expected states of design. Exploring the integration among the functional objectives, the expected behavior from various stakeholders, and the actual behavior observed in society, we facilitate a foundational examination of policy design. By incorporating diverse perspectives and considering the dynamic nature of societal expectations, it allows for a more nuanced understanding for decision-making. In this paper, we address the following: What is the utility of the function–behavior–structure (FBS) construct in designing public policy?