Language and communication improvement approaches designed by SLT services for delivery by early years practitioners can be effective in principle, but what helps or hinders initial and ongoing success? In this implementation study, we investigated the experiences of 10 practitioners who became Language Leads (LLs) and delivered the Language Lead Approach (LLA) in early years settings. Our participants were highly invested in the LLA and praised its benefits for children and for their emotional and professional development. However, within their settings, practitioners found staff attitudes and engagement and resource limitations were significant barriers to implementation. Managerial support was perceived as less important for implementation than anticipated from previous literature. LLs often felt frustration at time and staffing constraints and felt personally responsible when implementation was not complete. LLs experienced confusion in their first year delivering the LLA, needing more guidance and support from speech and language therapists (SLTs). Practical implications are explored to help services design and improve the implementation, and therefore effectiveness, of similar strategies.