Central nervous system (CNS) involvement in anaplastic large cell lymphoma (ALCL) is uncommon. CNS prophylaxis is not regularly included in second-line treatments for patients who develop CNS-negative relapses. We report a pediatric case of recurrent ALK-negative ALCL who developed isolated CNS progression during the treatment with brentuximab vedotin monotherapy. The patient achieved CNS remission after receiving the CNS-directed treatments including craniospinal irradiation. There is no evidence regarding whether brentuximab vedotin can cross the blood-brain barrier. CNS prophylaxis should be considered in high-risk patients with relapsed ALCL who receive second-line treatments containing agents with limited CNS penetration.