The following article provides a comprehensive guide to the clinical implementation of the Safety First Assessment Intervention (SFAI). The SFAI is a systemised, whole family approach for young people with high‐risk issues presenting in a mental health crisis. It is underpinned by the Safety First Model (Bickerton et al., [Bickerton, A., 2007]) and promotes community‐based care. The SFAI operationalises the foundation levels of the Safety First Model (SFM) through a highly structured clinical process. It draws on family systems theory, predominantly the work of Bowen ([Bowen, M., 1978]), to conceptualise distress through a multi‐generational systems lens and to prioritise the young person's natural support system (their family, friends, school and community) as their key resource. The SFAI engages this natural support system and facilitates open communication about symptoms, distress, safety and risk. This promotes a shared understanding of the key issues in a relational context and forms the basis of collaborative risk management. Thus, a system of safety emerges prioritising the family's role in optimising the young person's community‐based recovery. The need for pharmacotherapy and hospitalisation is therefore minimised. The article includes background theory, an outline of the structured assessment intervention and clinical techniques, including strategies for complex family situations. Specific strategies are illustrated with fictional vignettes. The work is based on the authors' accumulated experiences of working with young people and their families and carers in an acute Child and Adolescent Mental Health Service (CAMHS) for over a decade.