Abstract Background Health literacy can be defined as individuals’ motivation and skills to access, understand, evaluate, and utilize information to make decisions about their health. Despite Sorensen’s widely used definition encompassing both individual and population levels, also known as Public Health Literacy, it remains poorly detailed and is rarely taken into account by measurement tools. As evidenced by the Covid-19 health crisis, limited public health literacy impacts reluctance to accept government recommendations, vaccine hesitancy, and fosters mistrust of science and conspiracy theories in the health field. The main objective of this study was to derive specific public health knowledge and skills from public health professionals for the general population constituted the first step of the development of a public health literacy measurement tools. Methods A qualitative study, based on ten semi-structured interviews with public health professionals from various settings (academic, hospital, health prevention, and promotion), working across various public health fields (nutrition, sexual health, mental health), has been conducted since March 2024. Results Preliminary analysis identified three main themes: (1) fundamental concepts including identification of health determinants, epidemiology and the purpose of public health interventions, (2) critical skills including the assessment of the level of evidence and reliability of public health information, and (3) civic orientation including environmental impact on health and community approach to interventions. Conclusions These detailed insights will guide the creation of a valid measurement tool for public health literacy. This will facilitate the investigation of specific impacts on people’s adherence to public health interventions or messages and the development of actions targeting literacy in a more holistic manner. Key messages • Specific public health dimensions have been identified to enrich the existed definition of health literacy. • Public health concepts, reliability of public health information and community approach constitute the core of public health literacy.