A considerable minority of children are exposed to prolonged periods of repeated or multiple interpersonal traumas at an early age, yet few interventions exist for this vulnerable population. This current case study presents manualized trauma-focused cognitive behavioral therapy (TF-CBT) with a 6-year-old boy who had been exposed to multiple traumatic events. The boy presented with symptoms of post-traumatic stress disorder (PTSD), depression, attention deficit hyperactivity disorder (ADHD), oppositional defiant disorder (ODD), specific phobia, reactive attachment disorder, and psychosocial malfunction in several domains. After TF-CBT was implemented, he no longer met the criteria of PTSD, depression, ADHD, and specific phobia. He also improved in several domains of psychosocial function. In addition, the mother reported a better quality of the parent–child relationship, and they both demonstrated a better understanding of trauma reactions and how to apply new coping and problem-solving skills. Finally, the young boy showed improvements in academic performance, social interactions, and general emotional and behavioral functioning. This case study adds to the growing literature, highlighting the utility of using TF-CBT to successfully treat symptoms of PTSD and associated psychopathology in young children with a history of complex trauma.