Abstract Objective Low back pain is the leading cause of worldwide disability, with lumbosacral radiculopathy accounting for over one-third of these cases. There are limited data on the relationship between etiologies and lumbosacral radiculopathy, and it is unknown whether specific causes predict treatment outcomes. Design, Setting, and Subjects This study explores patient-reported etiologies for lumbosacral radiculopathy in a chronic pain clinic between January 2007 and December 2015 and examines whether these causes affected epidural steroid injection outcomes. Methods We reviewed the medical records of 1,242 patients with lumbosacral radiculopathy who received epidural steroid injections. The recording of an inciting event was done contemporaneously based on note templates. A positive outcome following an epidural steroid injection was defined as ≥30% pain relief sustained for six or more weeks without additional intervention. Factors associated with epidural steroid injection outcome were analyzed by multivariable logistic regression. Results Fifty point seven percent reported an inciting event, and 59.9% of patients experienced a positive epidural steroid injection outcome. The most commonly reported causes were falls (13.1%), motor vehicle collisions (10.7%), and lifting (7.8%). Individuals with a herniated disc (56.3%) were more likely to report a precipitating cause than those with stenosis (44.7%) or degenerative discs (47.8%, P = 0.012). An inciting event did not predict treatment outcome. Factors associated with negative treatment outcome included opioid consumption (odds ratio OR = 0.61, 95% confidence interval CI = 0.39–0.95, P = 0.027), secondary gain (OR = 0.69, 95% CI = 0.50–0.96, P = 0.030), and baseline pain score (OR = 0.90, 95% CI = 0.84–0.97, P = 0.006). The number of levels injected was associated with a positive outcome (OR = 2.72, 95% CI = 1.28–6.47, P = 0.008). Conclusions Reported inciting events are common in patients with lumbosacral radiculopathy but are not associated with outcome following epidural steroid injection, and their occurrence is not always consistent with the purported mechanism of injury.