Mental health, as a fundamental health indicator directly influencing quality of life, productivity, and social change, is both the foundation and the starting point of sustainable development. The World Health Organization defines spiritual well-being as the ability of an individual to realize their potential, cope with life stressors, and contribute to society. The benefits of the Sustainable Development Goals (SDGs) are not only the focus of SDG 3 (Healthy Distribution), but also sought through solutions such as SDG 1 (No Poverty), SDG 4 (Quality Education), SDG 5 (Gender Equality), SDG 8 (Decent Work and Economic Growth), and SDG 10 (Reduced Inequalities). While socioeconomic inequalities, poverty, low education, and gender issues increase the risk of mental disorders, changing mental well-being, increasing social inclusiveness, and increasing economic productivity contribute to sustainable development. Community mental health advocates, as key actors in this relationship, play preventive, protective, therapeutic, and rehabilitative regulatory roles. Nurses conduct risk assessment, psychoeducation, crisis intervention, psychosocial support, and community outreach at the field level, strengthening lifelong learning, reducing social stigma, and contributing to the elimination of inequalities. In achieving SDG targets, community mental health advocates stand out as a discipline that strengthens and documents not only individual health care but also social freedom, gender equality, educational opportunities, and psychosocial support in the workplace. In this context, the sustainability of mental health is a direct component of sustainable development, encompassing its social, economic, and growth dimensions. The multifaceted roles and responsibilities of community mental health advocates contribute to the effective and sustainable implementation of the SDGs by enhancing both individual liberation and the overall well-being of society. Mental health and sustainable development are considered two pillars that “ensure the continued sustainability of sustainable and social sustainability.”