To identify key factors influencing the therapeutic efficacy of the ketogenic diet (KD) for children with drug-resistant epilepsy and elucidate their interconnected relationships to optimize clinical practice. Participants were selected from children receiving KD treatment at West Second University Hospital of Sichuan University from September 2015 to October 2023. Clinical factors pre-KD and post-KD (at the third month) were analyzed systematically using an analytical framework. Descriptive analyses, univariate analyses, and multivariate regression analyses were performed for the entire cohort and subgroups of genetic and non-genetic (i.e., structural and unknown) etiologies. Thereby, the most significant predictors were identified for each relevant dependent variable. Path analysis diagrams were used for visual representation. Of 156 patients, genetic etiology was prevalent (38.5%). In the genetic subgroup, channelopathies predicted lower baseline seizure frequency and increased chance of seizure freedom with KD. Frequent seizures and complex history of anti-seizure medications (ASMs) predicted severe baseline psychomotor abnormalities. Younger age at KD initiation benefited psychomotor improvement. In the non-genetic subgroup, lower baseline seizure frequency increased the likelihood of seizure freedom post-KD. Concurrent use of multiple ASMs helped achieve ≥50% seizure reduction. Boys were more likely to experience psychomotor improvement. A significant correlation was found between ≥50% seizure reduction and psychomotor improvement in both subgroups. Delayed KD initiation (longer epilepsy duration at KD start) was related to a greater number of ASMs used, infrequent seizures, and older age at epilepsy onset. In addition, patients with channelopathies had delayed initiation of KD. Children with genetic epilepsy display more pronounced characteristics of epileptic encephalopathy. Early KD intervention is crucial for channelopathies, notably SCN1A variants. For other drug-resistant epilepsy cases, KD alongside diverse ASMs may improve seizure control and developmental outcomes. However, the patient population benefiting most from early KD tends to start the treatment later, urging a re-evaluation of KD decision-making paradigms.