Many National Health Service (NHS) Trusts in England have invested in dialectical behavioural therapy (DBT) for mental health service users. The experiences of NHS staff delivering DBT were explored using semi-structured interviews with six dialectical behaviour therapists working in secondary mental health services within the NHS. The aim was to consider the impact on staff of adding the DBT therapist role onto their existing job role. Interview data were analysed using thematic analysis. Six themes were inductively generated from the data: DBT as a useful framework; DBT as the most satisfying part of the job; ‘Worzel Gummidge heads’– conflicts in roles; ‘DBT buddies’– the importance of informal support; uncertainty about the future; and recursivity – using DBT skills personally. Interactions between themes, implications for the service and future research directions are discussed. Key findings suggest that the addition of the DBT therapist role, as well as the recursive nature of DBT, has a positive impact professionally and personally. However, the service context within which participants were working can lead this additional role to cause increased demands and therefore stress, reducing that positive impact.