Serratia marcescens is a significant opportunistic pathogen responsible for recurrent outbreaks in neonatal intensive care units (NICU) worldwide. Its ability to persist in the hospital environment, develop antimicrobial resistance, and spread through diverse transmission routes makes prevention and control particularly challenging, especially among vulnerable neonatal populations. This narrative review summarises published literature from 2015 to 2025 on S. marcescens infections in neonates, with a focus on outbreak characteristics, transmission pathways, clinical manifestations, outcomes, and infection control strategies implemented in NICU settings. Thirty-eight outbreaks reported across five continents were analysed. Most outbreaks predominantly affected preterm and very low birth weight infants, with bloodstream infection and sepsis representing the most common clinical presentations. Reported mortality rates varied widely, ranging from approximately 7% to over 60%, reflecting differences in patient populations, outbreak severity, and healthcare resources. Environmental reservoirs, including sinks, medical equipment, and surrounding surfaces, were the most frequently implicated sources of transmission, followed by healthcare workers’ hands and water-associated systems. Molecular typing methods, particularly pulsed-field gel electrophoresis and whole-genome sequencing, confirmed clonal transmission in a substantial proportion of outbreaks and proved essential for outbreak investigation and containment. Effective control measures included reinforcement of hand hygiene practices, thorough environmental decontamination, cohorting of colonised or infected neonates, and temporary reorganisation or closure of affected NICU areas. S. marcescens remains a persistent cause of neonatal outbreaks, underscoring the need for continuous surveillance, environmental monitoring, and standardised prevention strategies, particularly in resource-limited settings.