Treatment of lumbar disc herniation (LDH) using condoliase chemonucleolysis (CC) requires more time than surgery to demonstrate therapeutic effects. This study aimed to identify patients who show significant improvement in leg pain very early after CC and to determine pretreatment factors that can predict a very early therapeutic response. The study included 52 patients who underwent CC for treatment-resistant LDH. Scores for low back and leg pain measured by a numerical rating scale were assessed at four time points (1day, 1 week, 1 month, and 3 months after CC). Patients who reported subjective pain relief the day after treatment and further exhibited an improved straight leg raising (SLR) angle compared to pretreatment were classified as "very early responders (VER)". Of the 52 patients, 39 (75%) were VER, and 13 (25%) were non-VER. The VER showed earlier improvement in leg pain. The VER had a significantly higher proportion of positive SLR test patients (p = 0.01) and a significantly smaller pretreatment SLR angle compared to the non-VER (VER vs. non-VER: 40.6 ± 19.0 vs. 63.1 ± 16.9, p < 0.001). There were no significant differences in the level, type, and size of LDH and the disc regression rate between the two groups. Patients with a smaller pretreatment SLR angle are more likely to experience very early or early symptomatic relief, with a significant and sustained reduction in leg pain up to 3 months after CC treatment.