This paper reports on a case study that explored the broader contextual factors influencing the implementation of the CompHP Core Competencies at a country level in Ireland and Italy between 2011 and 2018. The sample comprised key informants who were Health Promotion experts and were knowledgeable about how the competencies had been used in their country. These experts formed National Reference Groups that guided the research process in each country and helped identify additional key informants. Qualitative methods were utilized consisting of a desk review and semi-structured interviews. The data from each country were analyzed separately using a thematic analysis approach, with the findings then compared and reviewed by the National Reference Groups. A total of 26 interviews were completed (13 in each country). The findings show that both the focus and rate of progress of implementing the competencies differed across the two countries and that this reflected their levels of Health Promotion infrastructure and capacity development. A lack of awareness of the competencies was identified as a major limiting factor in implementation in both countries, of particular concern in relation to employers and decision-makers. While the case study focused on implementing the competencies in two European countries, there are insights from their experience that can inform implementation in other countries. The study also begins to address the gap in empirical evidence on the use and impact of Health Promotion competencies and the factors that influence their implementation.