Background <p>Healthy-lifestyle-promoting practices are recommended to reduce the prevalence of non-communicable diseases and increase health, but are underutilized in Swedish primary health care (PHC). As part of the Act in Time project, a 12-month multifaceted implementation intervention to support the uptake of a clinical intervention offering lifestyle-screening forms and counselling to patients with planned visits, was evaluated in a PHC setting. This study aimed to explore the experiences of PHC professionals, internal facilitators, and managers working with health promotion after receiving the 12-month implementation intervention.</p> Methods <p>A qualitative study was conducted at five PHC units in Sweden using interviews with managers (<i>n</i> = 9) and internal facilitators (<i>n</i> = 10) and focus group discussions (<i>n</i> = 5) with physicians, nurses, counsellors, and physiotherapists (<i>n</i> = 18). The data were analysed with qualitative content analysis, first inductively and then deductively by mapping the data against the 12 constructs of Normalization Process Theory.</p> Results <p>Implementation of the health-promoting practice was affected by contextual factors such as attitudes and available resources. The group dynamics at the PHC centres and the managers’ role as leaders were important for finding solutions to enact the health-promotion practice.</p> <p>Health-promotion practice was seen as a natural development of PHC. A common focus and opportunity to influence created a sense of coherence. Feelings of autonomy enabled the professionals to collaborate and strengthened participation in the implementation intervention. The internal facilitators helped to guide the PHC centres forward in the implementation process and created strategies to integrate the health-promotion practice into existing clinical practice. </p> <p>Uptake of the clinical intervention led to a more structural and holistic way of working with lifestyle habits, with patients taking an active part. The professionals’ competencies became more visible by working together, but frustration was also expressed due to different levels of engagement in the health-promotion practice. </p> Conclusions <p>Health-promotion practice can be normalized as routine work in PHC with targeted support but requires tailored strategies that rely on existing group dynamics and the manager’s role. To create motivation for providing health promotion, inter-professional collaboration is a key factor that ensures shared ownership of the implementation intervention. </p> Trial registration <p>This study is part of the Act in Time project, registered at ClinicalTrials.gov on 4 March 2021 (ref NCT04 799860).</p>