The aim of this contribution is to explain how healthcare professionals implement policies for integrated care. More specifically, we aim to understand how these policies are received, interpreted and executed by primary care professionals. By opening the “black box” of policy implementation, we also explain how and why the process of implementation of the same policy diverges in practice. The research is framed according to both the neo‐institutional and the change management perspectives. The empirical investigation is conducted through a documental analysis and a multiple‐embedded case study. The results show that three forces affect and explain differences in the implementation processes: the unstable level of internal communication among the professionals involved, the limited use of power to resist to change and the poor learning process on the part of both the professionals and policy makers. The pressure of external institutions does not play a role in shaping the process. Through our study, we further knowledge about how healthcare professionals implement policies for integrated care, and we believe this is interesting, according to emerging evidence that variations in the effectiveness of policy outcomes may be explained by choices and potential distortions made during the initial stages of the policy implementation process. Copyright © 2015 John Wiley & Sons, Ltd. StartCopTextCopyright © 2015 John Wiley & Sons, Ltd.