Cost-effectiveness analyses of health care programs often focus on maximizing health and ignore nonhealth impacts. Assessing the cost-effectiveness of public health interventions from a narrow health care perspective would likely underestimate their full impact, and potentially lead to inefficient decisions about funding. The aim of this study is to provide a practical application of a recently proposed framework for the economic evaluation of public health interventions, evaluating an intervention to reduce alcohol misuse in criminal offenders. This cross-sectoral analysis distinguishes benefits and opportunity costs for different sectors, makes explicit the value judgments required to consider alternative perspectives, and can inform heterogeneous decision makers with different objectives in a transparent manner. Three interventions of increasing intensity are compared: client information leaflet, brief advice, and brief lifestyle counseling. Health outcomes are measured in quality-adjusted life-years and criminal justice outcomes in reconvictions. Costs considered include intervention costs, costs to the NHS and costs to the criminal justice system. The results are presented for four different perspectives: “narrow” health care perspective; criminal justice system perspective; “full” health care perspective; and joint “full” health and criminal justice perspective. Conclusions and recommendations differ according to the normative judgment on the appropriate perspective for the evaluation.