We present, to our knowledge, the first case of immunosuppressive therapy (IST) application in a 12‐year‐old child with arrhythmogenic inflammatory cardiomyopathy resulting from the overlap between autoimmune myocarditis and primary arrhythmogenic cardiomyopathy. Indication to off‐lable IST was compelling, because of recurrent drug‐refractory ventricular arrhythmias (VAs). We show that IST was feasible, safe, and effective on multiple clinical endpoints, including symptoms, VA recurrences, and T‐troponin release. Remarkably, all diagnostic and therapeutic strategies were worked out by a dedicated multidisciplinary team, including specialized pediatric immunologists.