The study of public health systems is an important, but very difficult task. The concept and functions of public health systems are influenced by the views, interests, and influence of the various stakeholders belonging to public health systems and broader social, economic, political, and environmental sectors. To define public health system with conceptual clarification, we must take into account the dynamic and complex aspect of the public health system. This paper reviews health systems and public health systems literature to suggest the concept, goals, and functions of public health systems. In addition, this paper recognizes some challenges, such as leadership and management, resource development, economic support, and service delivery to strengthen public health systems for improving health and well-being of population.