Legal intervention to influence individual health behavior has increased dramatically since the 1960s. This paper describes the rise of law as a tool of public health, and the scientific research that has assessed and often guided it, with a focus on five major domains: traffic safety, gun violence, tobacco use, reproductive health and obesity. These topical stories illustrate both law’s effectiveness and limitations as a public health tool. They also establish its popularity by the most apt of metrics – the willingness of legislators to enact it. The five examples demonstrate that public health law research can and does influence the development and refinement of legal interventions over time. Measuring the impact of laws can be difficult, but the field has the tools of theory and methods necessary to produce robust results. It is past time for public health research to receive institutional, professional and funding support commensurate with its social importance.