Sepsis, a serious condition characterized by life-threatening organ dysfunction owing to infection, lacks specific therapeutic interventions. Lactate serves as a crucial biomarker in sepsis, reflecting both the patient's metabolic state and the severity of the condition. Lactylation, the process whereby lactate is conjugated to lysine residues in proteins, profoundly alters protein structure and function. This review delves into the crucial roles of lactate and lactylation within the septic environment, illuminating the intricate feedback loop between metabolic reprogramming and lactylation in sepsis. Herein, fluctuations in lactate levels influence patterns of lactylation, which subsequently regulate energy metabolism. Lactylation is essential for modulating immune responses, adjusting gene expression profiles in immune cells, and shifting the balance between pro-inflammatory and anti-inflammatory pathways. The discovery of these pathways has significant implications for development of targeted therapies against sepsis. Furthermore, this review addresses the advancements and current limitations associated with lactylation research methodologies, and proposes new directions for future research. Overall, this narrative underscores the transformative potential of lactylation in understanding and managing sepsis, advocating for a multidisciplinary approach to unravel the complex interplay between metabolic processes and epigenetic regulation in critical illnesses.