Molecular aspects and organisational structure of HNF4α, and its key role in the regulation of transcription, metabolism, circadian rhythm, and other functions of the liver. Importance of HNF4α dysregulation in pathogenesis of liver diseases including, alcohol-associated hepatitis, hepatocellular carcinoma, steatosis, and coagulopathy. Current knowledge of how HNF4α interactions with nuclear receptors and target genes is disturbed in liver diseases.