Efforts to reverse the obesity epidemic require policy, systems, and environmental (PSE) change strategies. Despite the availability of evidence-based and other promising PSE interventions, limited evidence exists on the “how-to” of transitioning them into practice. For the past 13 years, the Los Angeles County Department of Public Health has been building capacity among community residents and other stakeholders to create effective community coalitions and to implement well-designed policy strategy campaigns using an evidence-based approach to policy change, the policy adoption model (PAM). Implementing a phase-based approach to policy change, the PAM was initially used to support the passage of over 140 tobacco control and prevention policies in Los Angeles County. Following these successes, Los Angeles County Department of Public Health applied the PAM to obesity prevention, operationalizing the policy process by training community residents and other stakeholders on the use of the model. The PAM has shown to be helpful in promoting PSE change in tobacco control and obesity prevention, suggesting a local-level model potentially applicable to other fields of public health seeking sustainable, community-driven policy change.