DNAX accessory molecule-1 (DNAM-1; CD226) is an activating immunoreceptor on T cells and NK cells. The interaction of DNAM-1 with its ligand CD155 expressed on hematopoietic and nonhematopoietic cells plays an important role in innate and adaptive immune responses. In this study, we investigated the role of the DNAM-1–CD155 axis in the pathogenesis of T cell–mediated Con A–induced acute liver injury. Unexpectedly, DNAM-1–deficient (Cd226−/−) mice exhibited more severe acute liver injury and higher concentrations of IL-6 and TNF-α than did wild-type (WT) mice after Con A injection. We found that a larger number of neutrophils infiltrated into the liver of Cd226−/− mice compared with WT mice after Con A injection. Depletion of neutrophils ameliorated liver injury and decreased IL-6 and TNF-α in Cd226−/− mice after Con A injection, suggesting that neutrophils exacerbate the liver injury in Cd226−/− mice. Hepatocytes produced more significant amounts of CXCL1, a chemoattractant for neutrophils, in Cd226−/− mice than in WT mice after Con A injection. In the coculture of hepatocytes with liver lymphocytes, either DNAM-1 deficiency in liver lymphocytes or CD155 deficiency in hepatocytes promoted CXCL1 production by hepatocytes. These results suggest that the interaction of DNAM-1 with CD155 inhibits CXCL1 production by hepatocytes, leading to ameliorating acute liver injury.