This advocacy document is intended for local elected officials and all professionals working for and within local governments. These local governments can take action to promote healthy aging among the population in their jurisdictions starting in midlife, that is, between the ages of 40 and 55. Its objectives are to raise awareness among local governments of their key role in supporting adults in midlife to prevent loss of independence and chronic diseases, a process that begins well before retirement; to help identify and engage the target audience; and to highlight the contribution of actions promoting prevention and health promotion in midlife to the fight against social and regional health inequalities. The advocacy highlights the following key points: Several studies show that the more health-promoting behaviors are adopted starting in midlife, the greater their cumulative beneficial effect on aging; An assessment of the health status of the population aged 40 to 64 living in France points to numerous concerning indicators: chronic diseases, early disability. This decline in health status is more pronounced among socioeconomically disadvantaged individuals; In 2023, in France, life expectancy at birth is 85.7 years for women and 80.0 years for men. However, before the age of 55, the proportion of remaining healthy life years has been decreasing since 2006. Research does indeed suggest an increase in severe disabilities among 50- to 64-year-olds in France. By 2050, people aged 60 and older will account for one-third of the population living in France. These figures call for action on health determinants through a comprehensive, multifactorial approach starting in midlife, as links between health-promoting lifestyle habits in midlife and healthy aging have been established. The more health-promoting behaviors are adopted starting in midlife, the greater the cumulative beneficial effect on aging; local governments effectively contribute to a local ecosystem and dynamics that may or may not encourage the adoption of health-protective behaviors. By influencing the environments and living conditions of the population, they can promote a balanced diet, regular physical activity, active mobility, quality sleep, access to healthcare professionals, and other “health-protective factors”; Local authorities can act as conduits for prevention messages, promote screenings, and encourage the use of preventive consultations, particularly within the framework of the new “My Prevention Checkup” program. Aimed primarily at adults aged 45 to 50, this check-up can facilitate the adoption of health-promoting behaviors. With no out-of-pocket costs for those covered by social security, the program offers an opportunity to reach populations that are typically underserved by the healthcare system.