Objective Resilience has been considered as a protective factor against stress. Evaluating resilience in firefighters and rescue workers, who are frequently exposed to traumatic events, is important and relevant. This study examined the psychometric properties of the Korean version of the Connor-Davidson Resilience Scale-2 (CD-RISC2). Methods Two-hundred twenty-two current professional firefighters and rescue workers were assessed by standardized, semi-structured clinical interviews and self-report questionnaires. Internal consistency, correlation with the CD-RISC, convergent validity, divergent validity, and predictive validity of posttraumatic stress disorder (PTSD) symptom severity were analyzed. Results The CD-RISC2 demonstrated good internal consistency (α = 0.75), item-total correlation (r = 0.89-0.90), and convergent and divergent validity. The total score of the CD-RISC2 showed significant correlations with the subtotal of the remaining 23 CD-RISC items (r = 0.77, p < 0.001) and with the score of each CD-RISC item (r = 0.15-0.66, all p < 0.05). The magnitude of the relationship between the number of traumatic experiences and PTSD symptom severity was greater in the low resilience group than in the high resilience group (p for interaction = 0.002). The likelihood-ratio test confirmed that the model predicting PTSD symptom severity based on the CD-RISC2 total score was not improved by the inclusion of subtotal scores of the remaining 23 CD-RISC items (χ2 = 0.31, p = 0.58). Conclusions These results suggest that the CD-RISC2 would be a valuable tool in evaluating resilience quickly and efficiently in firefighters and rescue workers.