Background The uptake, implementation, and maintenance of effective interventions promoting physical activity (PA) and a healthy diet and the implementation of policies targeting these behaviors are processes not well understood. We aimed to gain a better understanding of what health promotion professionals and policy makers think are important factors facilitating adoption, implementation, and maintenance of multi-level interventions and policies promoting healthy eating and PA in Belgium, Germany, Ireland, Norway, and Poland. Methods Six interventions and six policies were identified based on pre-defined criteria. Forty semi-structured interviews were conducted with stakeholders from various sectors to elicit information on factors impacting adoption, implementation, and maintenance of these interventions and policies. All interview transcripts were coded in NVivo, using a common categorization matrix. Coding in the respective countries was done by one researcher and validated by a second researcher. Results Active involvement of relevant stakeholders and good communication between coordinating organizations were described as important factors contributing to successful adoption and implementation of both interventions and policies. Additional facilitating factors included sufficient training of staff and tailoring of materials to match needs of various target groups. The respondents indicated that maintenance of implemented interventions/policies depended on whether they were embedded in existing or newly created organizational structures in different settings and whether continued funding was secured. Conclusions Despite considerable heterogeneity of interventions and health policies in the five countries, stakeholders across these countries identify similar factors facilitating adoption, implementation, and maintenance of these interventions and policies. Electronic supplementary material The online version of this article (10.1186/s12889-017-4929-9) contains supplementary material, which is available to authorized users.