Nonalcoholic steatohepatitis (NASH) is a progressive form of non-alcoholic fatty liver disease (NAFLD) and a significant risk factor for the development of cirrhosis and hepatocellular carcinoma. Despite the global prevalence of NASH, currently, there are no FDA-approved drugs for its treatment. In this study, we investigated the role of the E3 ubiquitin ligase, makorin ring finger protein 1 (MKRN1), and its relationship with AMP-activated protein kinase (AMPK), a target of MKRN1, in NASH. MKRN1 expression was significantly increased in liver samples from NASH patients compared to healthy individuals, while AMPK levels were decreased. Whole-body or liver-specific knockout of MKRN1 attenuated pathological manifestations of NASH, including hepatic steatosis, hepatocellular damage, inflammation, and hepatic fibrosis, in NASH models induced by a high-fat-high-fructose diet, methionine-choline deficient diet, or choline-deficient, L-amino acid-defined, high-fat diet. The therapeutic effect of MKRN1 inhibition was demonstrated by injecting NASH model mice with adeno-associated virus 8 (AAV8)-shMKRN1, which specifically targets MKRN1 mRNA in the liver. Furthermore, NQ1, a MKRN inhibitor, activated AMPK by destabilizing MKRN1, thereby suppressing NAFLD progression. These findings highlight the potential of MKRN1 as a novel therapeutic target to activate liver AMPK and treat NASH.