Background: Kawasaki disease (KD) is usually characterized as an inflammatory vasculitis during early childhood, which predominantly involves medium-sized arteries and is treated with intravenous γ-globulin (IVIG) and oral aspirin. KD with hemodynamic instability, characterized by systolic blood pressure decreasing by more than 20% below the normal range, is defined as Kawasaki disease shock syndrome (KDSS). The pathogenesis of KDSS is still not comprehensively understood. Life-threatening cardiogenic shock can occur during the acute phase of KDSS, while the mechanism of cardiac dysfunction due to KDSS is still controversial, and such cases are rarely reported. Here, we present the application of veno-arterial (VA) extracorporeal membrane oxygenation (ECMO) for cardiac function support of a child with KDSS. By doing so, it will be a reminder that KDSS can cause severe cardiac dysfunction, and we should stay vigilant at the early stage of the disease to distinguish KDSS from toxic septic shock in the first place and initiate the appropriate treatment at the right moment, in order to prevent such patients from having irreversible outcomes.