<p>To support healthy development of children and adolescents with disabilities, it is essential to understand the factors that promote life satisfaction among them. Guided by Bronfenbrenner’s ecological systems theory, this study examined whether family health and social activity participation are associated with life satisfaction in this population, and whether these relationships are mediated by self-esteem. Longitudinal data from 562 children and adolescents with disabilities were drawn from the Disability Life Panel Survey conducted by the Korea Disabled People’s Development Institute (2020–2022). Family health and social activity participation were measured at Wave 3, self-esteem at Wave 4, and life satisfaction at Wave 5. Structural equation modeling was used to analyze direct and indirect relationships among the study variables. Family health was both directly and indirectly associated with higher subsequent life satisfaction, establishing a pattern of partial longitudinal mediation. Conversely, social activity participation exhibited a non-significant direct relationship with life satisfaction, operating through a pattern of full longitudinal mediation. Meanwhile, self-esteem served as a critical mediating mechanism linking external environmental contexts with subsequent life satisfaction. The study highlights the importance of family-centered support and meaningful integrated social participation for promoting psychological well-being among children and adolescents with disabilities.</p>