This study investigated the relationship between Insomnia and Post-operative Pain (POP) in Athletes. We conducted a case-control study on individuals who had undergone microscopic lumbar discectomy. Based on their Insomnia Severity Index (ISI) ratings, participants were separated into two groups: insomnia groups (n = 35) and control groups (n = 35) for those with an ISI score of 7 or higher. Following 1, 2, 4, 8, 12, and 18 hours after surgery, all subjects were asked to rate their pain on a numeric rating scale (NRS). We selected athletes with a history of microscopic lumbar discectomy to reduce the possible impact of sleep deprivation on acute postsurgical pain in athletes due to changes in operative pathophysiology and techniques. Age, gender, BMI, American Society of Anesthesiologists score, and duration of surgery were comparable between groups. The subjects with insomnia had higher NRS scores and significantly more post-operative tramadol and rescue analgesia requirements than the controls. According to the covariant analysis, insomnia greatly affected the mean NRS score and strongly correlated with preoperative pain. In individuals undergoing microscopic lumbar discectomy, insomnia may serve as an effective predictor of acute POP, according to the findings of this study.