Public health has a long history and a contested meaning. Furthermore, public health operates in a social context and its messages may be rejected by the public. Nurses who have a direct public health role, notably those working in the community and in primary care, need to be able to articulate and discuss public health theory and practice, particularly in the context of the coronavirus disease 2019 (COVID-19) pandemic. This article provides an overview of public health, including its meaning and historical development, and discusses six essential elements of public health theory and practice in the context of the COVID-19 pandemic. These six essential elements are related to public health interventions provided by nurses and to Platform 2 of the Nursing and Midwifery Council’s standards of proficiency for registered nurses, which is particularly applicable to public health. The aim of the article is to support nurses to gain a better understanding of their role in public health.