Background The implementation of innovations in practice is a critical factor for change and development processes in health and home care. We therefore analyze how an innovative tool - a mobility agreement to maintain physical mobility of home care clients - was implemented in Finnish home care. Methods Our study involves ethnographic research of 13 home care visits, two years after the mobility agreement was implemented. We analyze the emergence of contradictions, the motives of the actors and the use of artifacts supporting or inhibiting the implementation. Two in-depth cases illustrate the implementation of the mobility agreement in home care visits. Findings Our findings show that, first, to achieve practice change and development, the innovation implementation requires the overcoming of contradictions in the implementation process. Second, it calls for the emergence of a shared motive between the actors to transform the abstract concept of an innovation into a concrete practice. Third, artifacts, customary to the clients are important in supporting the implementation process. Fourth, the implementation brings about a modification of the innovation and the adopting social system. Conclusions Innovation implementation should be seen as a transformation process of an abstract concept into a concrete practice, enabled by the actors involved. Concept design and implementation should be closely linked. In health/home care innovation management, the implementation of innovations needs to be understood as a complex collective learning process. Results can be far reaching - in our case leading to change of home care workers' professional understanding and elderly clients' mobility habits.