Purpose Cancer-related fatigue occurs frequently in patients with Hodgkin lymphoma (HL) and has a major impact on their quality of life. We hypothesized that severe fatigue (sFA) might have an impact on patients' treatment outcome and social reintegration. Methods Of 5,306 patients enrolled in the German Hodgkin Study Group's fifth generation of clinical trials in HL (HD13, HD14, and HD15; nonqualified and older [> 60 years] patients excluded), 4,529 provided data on health-related quality of life. We describe sFA (defined as a score ≥ 50 on the 0 to 100 scale from the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Core 30) before and up to 9 years after therapy and analyze its impact on treatment outcome and social reintegration. Results The proportion of patients reporting sFA was 37% at baseline and ranged from 20% to 24% during follow-up. Baseline sFA was associated with significantly impaired progression-free survival and a trend to impaired overall survival, which can be overcome in patients receiving highly effective HL therapies as applied in our fifth-generation trials. Our analysis revealed a significant negative association of sFA and employment in survivors: 5 years after therapy, 51% and 63% of female and male survivors, respectively, with sFA were working or in professional education, compared with 78% and 90% without sFA, respectively ( P < .001 adjusted for age, sex, stage, baseline employment status, and treatment outcome). sFA was also associated with financial problems and the number of visits to a general practitioner and medical specialists. Conclusion sFA is an important factor preventing survivors from social reintegration during follow-up. This observation underscores the need to address fatigue as a significant diagnosis when treating patients with and survivors of cancer.