A public health system has been described as 'a complex network of individuals and organizations that have the potential to play critical roles in creating the conditions for health' (Institute of Medicine). The idea of such a system is not new and draws heavily on the work of the World Health Organization. This paper assesses the state of the public health system in England as it has evolved since the mid-1970s, based on a scoping study commissioned by the National Institute for Health Research (NIHR) Service Delivery and Organization to inform its public health research programme. It identifies the principal components of the ideal public health system, and explores the challenges facing those seeking to devise a more coherent and effective system. The paper concludes that despite public health being high on the policy and political agendas, the prominence given to it has yet to be matched by success across the system as a whole. There is also a need to address what is perceived to be policy incoherence, and an absence of joined-up thinking. Tackling problems such as the obesogenic environment demands a whole-systems approach that cuts across government, as well as requiring action by industry, communities, families and society as a whole.