This qualitative study explored the vital role of line managers, namely the managerial level directly above employees, in effectively implementing evidence-based practice (EBP) from their own perspectives. Interviews were carried out with twenty-eight line managers within social services and older people care in seven Swedish municipalities. Thematic analysis was performed. Findings revealed that managers in social care perceived their role as important in implementing EBP. However, notable differences were observed between the two settings, where social services managers had more knowledge and held more positive attitudes towards working according to EBP, and described a more active role in the implementation process than managers in older people care. Overall, the implementation of EBP was performed ad hoc rather than systematically, and with little consideration to analysis of needs according to the local context and limited focus on follow-up and sustainability. This study highlighted that line managers in social services and older people care have different prerequisites for implementing EBP, and are greatly dependent on organisational strategies and context. Gaining knowledge of line managers’ perceptions is essential for making informed decisions regarding the support required to achieve EBP in social care, and thus for providing the best possible care for clients.