Chronic low-grade inflammation (CLGI) plays a key role in metabolic deterioration in the obese population. Jak3 expression and activation provide protection against development of CLGI and associated health complications. Studies in rodent model show that loss of Jak3 results in increased body weight, basal systemic CLGI, compromised glycemic homeostasis, hyperinsulinemia, and early symptoms of liver steatosis. Lack of Jak3 also results in exaggerated symptoms of metabolic syndrome by western high-fat diet. Mechanistically, it is shown that Jak3 is essential for reduced expression and activation of toll like receptors (TLRs) in murine intestinal mucosa and human intestinal epithelial cells where Jak3 interacted with and activated p85, the regulatory sub-unit of the PI3K, through tyrosine phosphorylation of adapter protein insulin receptor substrate (IRS1). These interactions resulted in activation of PI3K-Akt axis, which was essential for reduced TLR expression and TLR associated NF-κB activation. Overall, Jak3 plays an essential role in promoting mucosal tolerance through suppressed expression and limiting activation of TLRs thereby preventing intestinal and systemic CLGI and associated obesity and MetS.