Background Definitive chemoradiotherapy (dCRT) is widely accepted for esophageal squamous cell carcinoma (ESCC), although the outcomes can vary. Therefore, we aimed to develop a nomogram for the pre-treatment prediction of survival after dCRT for ESCC. Methods This retrospective study evaluated 204 patients (169 patients in a primary cohort and 35 patients in a validation cohort) who received dCRT for ESCC between July 2013 and June 2017. Results Pre-treatment parameters that predicted long-term survival in this setting were body mass index (BMI), absolute lymphocyte count (ALC), neutrophil-to-lymphocyte ratio (NLR), wall thickness, concurrent chemoradiotherapy, radiotherapy modality, and American Joint Committee on Cancer (AJCC) stage. The nomogram incorporated these factors and provided C-index values of 0.691 [95% confidence interval (CI): 0.641–0.740] in the primary cohort and 0.816 (95% CI: 0.700–0.932) in the validation cohort. The calibration curve analysis revealed that the nomogram had good ability to predict 2-year progression-free survival (PFS). The nomogram also performed better than the AJCC staging system by the C-index values (0.691 vs . 0.560) and the area under the curve values (0.702 vs . 0.576). Decision curve analysis (DCA) also indicated that the nomogram had better clinical utility. Conclusions These results suggest that pre-treatment parameters may help predict the efficacy of dCRT for ESCC. Furthermore, as the nomogram provided better prognostic accuracy than the AJCC staging system, the nomogram may be useful in clinical practice for prognostication among patients who are going to receive dCRT for ESCC.