Inter‐professional collaboration remains a significant concern within healthcare and social care. However, there has been scant attention paid to practices at the interface of clinicians and carers, namely foster carers and residential carers. The present study considers child and adolescent self‐harm management and prevention practices as a site of empirical interest due to reports that multi‐agency teams are not effectively operating. Drawing upon a grounded theory approach, data were generated via semi‐structured interviews and focus groups with residential carers (n = 15) and foster carers (n = 15) in Wales. Themes were developed through axial coding. The results present two central themes to explain the nature and perceived causes of inter‐professional discord. First, there are clear contestations in expertise, with carers challenging clinicians’ propositional knowledge in favour of their own experiential expertise. However, participants simultaneously endorse medical dominance, which contributes to their sense of disempowerment and marginalisation. Second, is the preclusion of carers’ professional identity, primarily due to inadequate professionalisation procedures. Meanwhile, the privileging of their parenting role is perceived to support the perpetuation of courtesy stigma. Carers are then compelled to undertake the effortful labour of legitimisation. Together these thematic insights provide direction on mechanisms to improve inter‐professional interactions, notably around training and accreditation.