The article examines the role of psychodynamic formulation in directing clinical rehabilitation following acquired brain injury, focusing on the contribution of Kohut’s theory of self-psychology. This is based on a case study of a man showing poor emotional and functional recovery following mild traumatic brain injury. Self-psychology formulation was used to understand psychopathology and guide psychodynamic therapy. The brain injury itself served as a severe narcissistic injury, which threatened self-worth and triggered distress. In addition, the patient was particularly vulnerable to narcissistic injury, due to a relational trauma as an infant in which presumably he was deprived of socio-emotional learning during right brain development. This postulates how detrimental early socioaffective experiences provided a growth-inhibiting environment for his developing brain. Thus, his poor recovery may be the outcome of two consecutive brain injuries: one developmental, due to relational trauma, and the other acquired as an adult following a road traffic collision. This helps provide a satisfactory formulation as to why a mild brain injury can result in devastating functional and emotional outcomes. The therapeutic work focused on constructing a sense of coherent self as a means to correct for unsatisfactory self-object experiences in early life and current family dynamics. It is hoped that the article contributes to the growing understanding of the central role childhood experiences can play in shaping the adult’s reactions to a traumatic brain injury, as well as the complex relationship with pre-injury personality, injury severity, and functional outcome.