Objective Debate concerning the diagnosis of mental health problems has accelerated since the publication of the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM‐5). Despite this, little is known about how multi‐disciplinary teams work together in the face of differing views. Method Constructionist thematic analysis was used to analyse data from semi‐structured interviews conducted with 20 mental health clinicians based at three acute child and adolescent mental health care units. Case discussions in team meetings were also observed. Results Views regarding diagnosis were largely a function of the role of team members and stratified according to hands‐on involvement with young people. Nurses saw it as the least relevant to their practice, clinical psychologists and other allied health professionals were the most critical, and psychiatrists were the most pragmatic about the benefits. Despite these differences, and with a few exceptions, team unity was possible through dialogue regarding formulation. Conclusion Despite academic debates regarding diagnosis, professionals in acute mental health settings can work together effectively if united by psychological formulations.