Huge supratentorial ependymomas are rarely encountered tumors, even in the infant population. A recovery from complete hemiplegia following a tumor resection including the primary motor cortex was observed. A 5-month-old girl presented with a conjugate deviation to the right and a head circumference that had gradually expanded since birth. Magnetic resonance imaging (MRI) demonstrated a well-enhanced huge mass extending into the right hemisphere. A subtotal removal with the primary motor cortex was performed. However, a regrowth of the residual tumor was observed and, thereafter, the patient underwent a subsequent surgical intervention 5 months later. The histological findings demonstrated an ependymoma. Her motor function was dramatically improved after rehabilitation and no tumor recurrence was detected for 10 years. A diffusion tensor imaging study showed that the motor fibers arose from the residual frontal lobe. The successful surgical management of ependymoma may depend on a total microscopic resection. In a case demonstrating a huge ependymoma, we had to remove a very thin motor cortex with the tumor. However, the motor function recovered completely. The motor damage inflicted at an early developmental age may be fully compensated due to the neuroplasticity of the residual brain.