Flavored tobacco products appeal to youth, and jurisdictions have implemented policy interventions to reduce youth tobacco initiation. This study reviews the process, challenges, and compliance monitoring of a flavored tobacco sales restriction. New York City (NYC) passed a policy restricting the sale of flavored non-cigarette tobacco products in 2009. To describe the policy's passage, legal defense, implementation, and enforcement, we conducted stakeholder interviews, reviewed legislative and legal records, and analyzed administrative data on retailer inspections and violations. Extensive public and policy maker education efforts preceded this policy. Barriers included opposition to the policy's passage and a tobacco manufacturer's lawsuit that sought to halt the law's implementation and to establish that NYC lacked the authority to restrict the sale of flavored products. The city implemented the flavored tobacco policy as intended and it withstood legal challenges. NYC integrated enforcement into the city's retailer compliance monitoring infrastructure, and the violation rate is low. Our investigation of NYC's experience with flavored tobacco policy implementation and enforcement can provide policy makers and health professionals with insights relevant to policy implementation, expand understanding of the potential impact of these kinds of policies, and inform compliance monitoring efforts.