<p>National governments play an essential role in supporting sustainability at the local level. However, they often struggle to design policies that are both coherent at scale and responsive to local diversity. Current approaches often shift between one-size-fits-all strategies, which overlook local variation, and fully customized interventions, which are resource-intensive and difficult to scale. This paper addresses this policy dilemma by proposing a three-step, data-driven approach that supports evidence-based differentiation of national urban policies, drawing on insights from archetype analysis in sustainability research. Step 1 involves developing sustainability profiles by combining environmental and socioeconomic indicators. Step 2 examines how commonly used policy criteria, such as provincial affiliation, urban typology, and population size, relate to these profiles. Step 3 identifies the issues that most strongly drive performance within each group, guiding the design of interventions. Applied to 171 cities across Canada’s ten provinces, the approach demonstrates how urban sustainability indicators can be used to determine when, how, and to what extent policies should be differentiated. While population size emerges as a consistent differentiator, regional and typological dynamics also influence outcomes, revealing distinctive strengths and weaknesses in both high- and low-performing cities. In contrast to static city classifications, this paper introduces a decision-support tool that adapts place-based policymaking to reflect local strengths, vulnerabilities, and policy goals.</p>