This study explores how child trauma is considered in disorder diagnosis with children and young people in Ireland. This grounded theory study conducted 1-1 semi structured interviews with 12 child and adolescent psychologists and psychiatrists, working in mental healthcare, in Ireland. The participants interviews, conducted in person, and online, via zoom, represent a diverse demographic, of age, (28-68 years approx.) gender (7 female, 5 male) and work contexts (perinatal hospital, training university, child and adolescent mental health services, and private practice). A constructivist grounded theory methodology (Charmaz, 2006) was used to analyse the transcribed interview data with an iterative process of coding, categorising, of observing and elevating emerging patterns, facilitating the emergence of the substantive theory of Holding - the Contentious Balance. Reflective memos were instrumental throughout the conduct of this study, demonstrating personal learning challenges and informing operational processes that directed analysis towards the emerging theory. The findings contribute a rich insight into this understudied phenomenon, presenting the Contentious Balance as the main concern. This Contentious Balance represents the practice challenges and dilemmas, of how this sample, balance the ‘subjective, movable’ nature of child trauma, within the ‘fixed rigid’ diagnostic frameworks that this cohort, are ‘under systemic pressure’ to employ. The findings identify that this tense engagement between child trauma and disorder diagnosis, is undergirded by an intersecting category; ‘tolerating uncertainty’ that influences this samples, actions, and interactions to child trauma in diagnostic practice. In the light of the findings and current national and international diagnostic literature, the study identifies the practice challenges and the underlying difficulties of balancing the complexity of child trauma, when intersecting with disorder diagnosis, in practice. The study explores the properties underlying these findings and the influences and implications on professionals working with child trauma in mental health care. Whilst acknowledging the challenges and dilemmas experienced by this sample, represented in the core category of the Contentious Balance, this study proposes an alternate theoretical framework to resolve this main concern, urging a ‘Holding’ position that is focused on a recovery approach, to a child impacted by trauma. The study identifies the implications of ‘Holding - the Contentious Balance’ on psychotherapy, and the wider field, as child trauma is considered in disorder diagnosis.