Approximately 1 in 10 U.S. newborns are born preterm (<37 weeks of gestation), facing risks of low birth weight, respiratory and birth deficits often requiring surgery, mechanical ventilation, and prolonged sedation. Such long-term exposure to sedatives in these babies can potentially pose neurodevelopmental risks and can further impact changes later in life. The present study focused on midazolam (MDZ), a benzodiazepine class drug commonly used as sedative in the neonatal intensive care unit (NICU). Using a robust preclinical rodent model mimicking chronic MDZ exposure, we did a comprehensive characterization on the phenotypic, molecular, biochemical, and behavioral outcomes in these exposed neonates across key developmental milestones. Our findings indicate that long-term MDZ exposure during the neonatal period negatively affects physical attributes in early childhood. While adult bodyweights between control and MDZ-exposed rats remain comparable, the MDZ rats exhibit accelerated and robust weight gain, potentially indicating a predisposition for binge eating behavior. Additionally, dopamine release in MDZ-exposed rats is markedly reduced in adulthood. Elevated levels of pro-inflammatory cytokines and growth factors in the brain during adulthood suggest a shift in development due to early MDZ exposure. Further, trends of heightened anxiety-like behavior and reduced social interaction during early adolescence compared to other stages were observed. Collectively, our study provides a comprehensive assessment of how long-term MDZ exposure during neonatal stages impacts outcomes throughout life, laying the foundation for understanding mechanisms that contribute to neurodevelopmental complications associated with long-term MDZ use in neonates.