Many studies have revealed that gut microbes modulate host metabolism. In this study, we characterized the therapeutic effects of a novel gut commensal Luoshenia tenuis against host metabolic disorders. First, by in silico analysis, we demonstrated that the L. tenuis was prevalent in the gut microbiomes of healthy humans but were depleted specifically in obesity cohorts. Further in vitro cultivation revealed that L. tenuis produced short chain fatty acids that were verified to modulate host metabolism and some other volatile metabolites to benefit hosts by anti-inflammation and anti-tumor. Second, gavage of the L. tenuis significantly decreased the body weight gain and food intake of high-fat diet-feeding C57BL/6J mice, which was in parallel with the changed expression level of genes related to satiety and feeding behavior. We then performed the gavage trial using diet induced obese mice, and it revealed that the administration of L. tenuis alleviated significantly the abnormal glucose and lipid metabolisms and reduced the inflammatory response. In summary, this study revealed a previously-unknown human gut commensal microbe that benefited host metabolism, and set the stage for the development of novel next-generation probiotic applicable for treatment of obesity and related metabolic disorders.