As populations continue to grow and age, there will be increasing demand for acute curative services responsive to life-threatening emergencies, acute exacerbation of chronic illnesses and many routine health problems that nevertheless require prompt action. Emergency interventions and services should be integrated with primary care and public health measures to complete and strengthen health systems. This paper focuses on acute care within that context. First, we draw on standard World Health Organization (WHO) terminology to propose working terms to define “acute care”. Second, we highlight the fragmentation of service delivery that results from not adopting the proposed definition. Third, we show the potential contribution of acute care to integrated health systems designed to reduce all-cause morbidity and mortality. Finally, we propose key steps to further the development of acute care that leaders, researchers and health workers, who are the people responsible for maintaining strong national health systems, should consider taking.