The aims of this research were to explore custodial prison staff and male prisoners’ perceptions toward self-harm, prison system responses and environmental impacts on self-harm. Four staff focus groups (thematic analysis) and 12 semi-structured interviews with male prisoners (interpretative phenomenological analysis) took place in three prisons in England. Prison staff attributed manipulative intention to self-harm; self-harming prisoners felt misunderstood. The prison environment and formal response processes were barriers for care access and provision. Recommendations include staff training in understanding and management of self-harm, supported by a care-focused culture, and fostering safety, security, empowerment and value for both prisoners and staff.