Background: Neonatal hypothermia is a major cause of preventable morbidity and mortality, especially among the world's poorest newborns. A heat-producing wrap is necessary when kangaroo mother care (KMC) is insufficient or unavailable, yet there is little published research on such wraps. The Dream Warmer is a wrap designed to complement KMC and has been extensively studied in formal research settings but not in real-world conditions. Objectives: We used implementation science methodology to understand the safety, effectiveness, and functionality of the Dream Warmer (hereafter, "Warmer"); its effect on clinical workflows; its interaction with other aspects of care such as KMC; and the Warmer's reception by healthcare providers (HCPs) and parents. Methods: We conducted a prospective, interventional, one-arm, open-label, mixed-methods study in 6 district hospitals and 84 associated health centers in rural Rwanda. Our intervention was the provision of the Warmer and an educational curriculum on thermoregulation. We compared pre and post intervention data using medical records, audits, and surveys. Findings: The Warmer raised no safety concerns. It was used correctly in the vast majority of cases. The mean admission temperature rose from slightly hypothermic (36.41 °C) pre, to euthermic (36.53 °C) post intervention (p = 0.002). Patients achieved a temperature ≥36.5 °C in 86% of uses. In 1% of audits, patients were hyperthermic (37.6-37.9 °C). Both HCPs and parents reported a generally positive experience with the Warmer. HCPs were challenged to prepare it in advance of need. Conclusions: The Warmer functions similarly well in research and real-world conditions. Ongoing education directed toward both HCPs and parents is critical to ensuring the provision of a continuous heat chain. Engaging families in thermoregulation could ease the burden of overtaxed HCPs and improve the skill set of parents. Hypothermia is a preventable condition that must be addressed to optimize neonatal survival and outcome.