Triage in emergency departments (EDs) is a dynamic decision-making process to prioritize patients based on their medical care needs. The Emergency Severity Index (ESI) is a simple-to-use, five-level triage system that categorizes ED patients according to clinical urgency. The triage nurse’s ability to obtain a brief history and rapidly assess clinical urgency is crucial for ensuring safe and efficient emergency care. This study aimed to assess the ability of registered triage nurses to accurately identify pediatric patients classified as Priority 1 (P1) and Priority 2 (P2) under the ESI, ensuring timely, life-saving interventions for critically ill children. A prospective chart review was conducted over six months, including all pediatric patients (aged 0–16 years) presenting to the ED and categorized as P1 or P2. Demographic data such as age, weight, gender, presenting complaints, vital signs at presentation, treatments administered in the ED, length of stay, and final disposition (admitted or discharged) were collected. Data were presented as mean ± SD or percentages with ranges. The association between the triage category and outcomes was assessed using the chi-square test. A total of 503 pediatric cases were included, with a mean age of 2.96 ± 3.79 years. The cohort comprised 311 male (62%) and 192 female patients (38%), with 250 patients (50%) under one year of age. Most patients (n = 308, 61%) were categorized as P2. Respiratory difficulties and fever were identified in 167 (33%) children, followed by cough/shortness of breath (SOB), fall/road traffic accident (RTA), and seizures. Among P1 cases, 11 patients (2%) required ventilatory support. A total of 384 patients (76%) were admitted to the hospital, with 297 (60%) admitted to general wards, primarily P2 cases. Significant associations were observed between triage category and outcomes, including seizures/febrile fits (P1: 20.5% vs. P2: 11.4%, P = 0.005) and pediatric intensive care unit (PICU) admissions (P1: 26.1% vs. P2: 5.1%, P < 0.001). Outcome measurements, like hospitalization, mode of admission (PICU or special care unit), mortality, length of stay in ED, cost of ED stays, and resources utilized, were all dependent on the initial triage categorization. The ESI triage system demonstrated its predictive value in determining urgency and guiding subsequent clinical decisions.