Exposure to repeated sexual trauma, particularly during childhood, often leads to protracted mental health problems. Childhood adversity is specifically associated with complex posttraumatic stress disorder (PTSD) presentation, which is particularly tenacious and treatment refractory, and features severe emotion dysregulation. Augmentation approaches have been suggested to enhance treatment efficacy in PTSD thus integrating first-line psychotherapy with mechanistically informed self-neuromodulation procedures (i.e. neurofeedback) may pave the way to enhanced clinical outcomes. A central neural mechanism of PTSD and emotion dysregulation involves amygdala hyperactivity that can be volitionally regulated by neurofeedback. We outline a treatment rationale that includes a detailed justification for the potential of combining psychotherapy and NF and delineate mechanisms of change. We illustrate key processes of reciprocal interactions between neurofeedback engagement and therapeutic goals. We describe a clinical case of a woman with complex PTSD due to early and repetitive childhood sexual abuse using adjunctive neurofeedback as an augmentation to an ongoing, stable, traditional treatment plan. The woman participated in (a) ten sessions of neurofeedback by the use of an fMRI-inspired EEG model of limbic related activity (Amygdala Electrical-Finger-Print; AmygEFP-NF), (b) traditional weekly individual psychotherapy, (c) skills group. Before and after NF training period patient was blindly assessed for PTSD symptoms, followed by a 1, 3- and 6-months self-report follow-up. We demonstrate mechanisms of change as well as the clinical effectiveness of adjunctive treatment as indicated by reduced PTSD symptoms and improved daily functioning within this single case. We outline an integrative neuropsychological framework for understanding the unique mechanisms of change conferring value to conjoining NF applications with trauma-focused psychotherapy in complex PTSD.