Publicly financed health systems face an urgent convergence of fiscal, demographic, and epidemiological pressures, including population ageing, multimorbidity, lifestyle-related chronic disease, and rising labor-intensive costs, that render predominantly reactive care models economically unsustainable. This chapter argues that longevity medicine—anchored in primary prevention, predictive risk stratification, validated biomarkers, and multidisciplinary, data-enabled care—offers a credible strategy to extend healthy life years, reduce chronic disease burden, and optimize resource allocation. We emphasize practical implementation through publicly accessible longevity clinics, operationalized with standardized assessment, stepped-care pathways, integrated digital records, and measurable functional and economic endpoints. Recognizing the limits of monolithic macro-reform, we propose a hybrid policy mix organized via the NATO framework (Nodality–Authority–Treasure–Organization), sequenced to balance early wins, fiscal realism, and workforce readiness: information infrastructures and citizen-facing tools; regulatory and accreditation standards for biomarkers and clinics; prevention-focused financing and equitable subsidies; organizational delivery models through community hubs and carefully governed PPPs; and workforce development to support multidisciplinary, data-literate teams. Additional considerations include phased piloting, pragmatic evaluation using healthspan-relevant outcomes, and climate-adaptive interventions to protect vulnerable populations, highlighting a systemic, evidence-driven roadmap for sustainable public health reform in the era of longevity.