Background There is an increasing prevalence of children/young people with long‐term conditions (LTC) in the UK due to improvements in health‐care management and delivery. These children are often involved, from an early age, in their own care and management; yet, there are little data to support how or when they develop the necessary skills and knowledge to become competent at this care. Objective This study aimed to understand self‐management of haemophilia, from a child's perspective, in the 21st century in the UK where intensive prophylactic therapy is given from early childhood. Design A qualitative study using grounded theory to evaluate life‐experiences of children and young people with haemophilia. Setting and participants Thirty boys aged 4–16 with severe haemophilia treated at a single paediatric haemophilia care centre were interviewed at home or in a focus group. Intervention/variables Multimethod qualitative research including age‐appropriate research tools (draw and write, photo‐elicitation and interviews) to facilitate data collection from children. Results Boys develop self‐management skills over time. They learn from health‐care professionals, their parents and other family members with haemophilia. Discussion Self‐management skills (bleed recognition, self‐infusion, self and medicines management, pain and risk management and conceptualizing preventative therapy) are developed through experiential learning and individualized education, and not through formalized expert patient programmes. Conclusion The boys in this study have benefited from early prophylactic factor replacement therapy. They develop skills in haemophilia and self‐management at a relatively young age and are experts in their own haemophilia care.