The prognosis for relapsed Hodgkin lymphoma after allogeneic hematopoietic cell transplantation (HSCT) is poor, partly because of limited treatment options. Here we present a case of a Hodgkin lymphoma patient who relapsed after allogeneic HSCT but remains in complete remission (CR) at 38 months from the start of extended brentuximab vedotin (BV) dosing. A 33-year-old man with refractory and relapsed nodular sclerosis classical Hodgkin lymphoma who underwent previous treatments, including adriamycin, bleomycin, vinblastine, and dacarbazine (ABVD) ; seven combination regimens; and autologous HSCT, prior to allogeneic HSCT achieved CR after three cycles of BV. BV was continued for 26 cycles and then discontinued because of a neurogenic bladder. The other adverse effects were mild paresthesia in the fingers, mild dysgeusia, and fatigue. The patient still remains in CR at 38 months from the start of BV. Thus, extended BV dosing may be a treatment option for relapsed and refractory Hodgkin lymphoma after allogeneic HSCT.