BACKGROUND: Health promotion in schools can be defined as any activity undertaken to improve the health of all school users. This qualitative study aimed to explore the systems of health promotion in primary schools in the aftermath of the COVID-19 pandemic, from the perspectives of teachers and principals in the Republic of Ireland. METHODS: Participants were recruited using snowball and convenience sampling techniques via a larger quantitative study. Participants joined 45-min online focus groups informed by a semi-structured interview guide. A reflexive thematic approach was taken to analysis. RESULTS: Thirty teachers participated, and most (n = 26) identified as female. Teaching experience across the sample ranged from 2 to 38 years. School sizes ranged from 20 to 850 students. All types of eligible publicly funded schools were represented. Three themes were generated: rebuilding the foundation, choosing within our limits and drawing the line. CONCLUSION: Findings indicate that systems of health promotion in primary schools were severely challenged during the COVID-19 pandemic and that recovery will be lengthy. School communities are well-positioned to have a leading role in primary and secondary disease prevention, but investment is needed to establish resilient frameworks for health promotion as child health issues provoked by the pandemic are addressed over the coming years.