Morchella esculenta is an edible mushroom known for its high nutritional value and delicious taste. Morchella esculenta polysaccharide has many biological properties, including neuroprotective, nephroprotective, anti-proliferating, tumor-suppressive, and immunostimulatory functions. In this study, Morchella esculenta Polysaccharide (MEP) was evaluated for its anti-inflammatory effects in adipose and liver tissue and for effects on obesity and obesity-associated conditions in High-Fat Diet (HFD)-induced obese mice. After MEP administration, HFD mice exhibited lower body weight, epididymal and subcutaneous fat deposition, and adipocyte sizes, as well as lower Aspartate Aminotransferase (AST), Alanine Aminotransferase (ALT), Triglycerides (TG), Total Cholesterol (TC) and Fasting Blood Glucose (FBG) than HFD control mice. Furthermore, MEP supplementation attenuates inflammation in the adipose and liver tissue via regulation of Toll-like Receptor 4 (TLR4) and inactivation of nuclear factor kappa B (NF-κB). It also regulates the expression of transforming growth factor beta (TGF-β) and pro-inflammatory cytokines. Moreover, MEP administration restores insulin resistance via inhibiting insulin receptor substrate-1 (IRS-1) in the adipose and liver tissue. In conclusion, MEP may be a promising pharmaceutic approach for body weight reduction, attenuating obesity, and inflammation.