Abstract This article explores the experiences of keyworkers within a third-sector employability programme targeted at people furthest from work. Using semi-structured qualitative interviews, the study investigated keyworker perspectives on effective elements of programme design, and what made the critical difference for those who did move into employment. Echoing previous research, findings confirmed the value of a holistic and personalised approach founded upon a consistent and long-term relationship of trust and support, through which programme participants developed the confidence and self-belief that was critical to progression towards employment. However, critical attention to the keyworker perspective offers novel insights, bringing to light challenges in defining role parameters and maintaining personal-professional boundaries in the interests of keyworkers and programme participants. We contribute to the body of research on employability practitioner perspectives, revealing that the strengths of person-centred support may simultaneously present tensions and wellbeing risks, where role parameters are very broadly defined.