Health systems are undergoing profound transformation under the combined pressures of population ageing, the growing prevalence of chronic conditions, and the rapid digitalization of care. These changes are not only clinical or technological but fundamentally organizational, requiring a reconfiguration of structures, governance, and professional roles. Traditional acute, hospital-based models are increasingly misaligned with the long-term, complex needs of ageing societies, demanding integrated, person-centered, and territorially grounded forms of care. This chapter explores the organizational challenges and opportunities arising from these transitions, drawing on insights from organizational theory, international case studies, and policy frameworks. It examines the paradigm shift from acute to chronic care, the need for adaptive leadership and learning health systems, and the strategic integration of prevention, equity, and sustainability into organizational design. Special attention is given to the role of digital innovation, including telemedicine, artificial intelligence, and data governance, as both enablers and disruptors of organizational transformation, highlighting the importance of ethical safeguards, participatory governance, and digital equity. Further sections analyze territorial health models, innovation ecosystems, and the European policy horizon for integrated care, emphasizing the role of collaboration across sectors and levels of governance. The chapter argues that demographic and digital transitions must be addressed as systemic organizational challenges that require new capabilities in coordination, inclusiveness, and resilience. Ultimately, building sustainable health systems in ageing and digital societies depends on reimagining organizations as adaptive, participatory, and ethically grounded ecosystems that align technological potential with social purpose.