Cirrhosis is no longer viewed solely as an isolated hepatic disorder but rather as a complex multisystemic disease that affects cardiovascular, renal, pulmonary, metabolic, and immune systems. One of its most clinically relevant but under-recognized consequences is cardiac dysfunction, manifesting as cirrhotic cardiomyopathy, portopulmonary hypertension, right ventricular (RV) failure, and impaired myocardial strain. Oxidative stress (OS) has recently emerged as a fundamental mechanistic link between hepatic fibrogenesis and myocardial remodeling, acting through mitochondrial injury, NADPH oxidase activation, nitric oxide dysregulation, iron-mediated ferroptosis, and inflammatory cytokines. These alterations lead to diastolic dysfunction, autonomic imbalance, myocardial fibrosis, electrophysiological abnormalities (including QTc prolongation), and impaired RV–pulmonary artery coupling. Redox biomarkers such as malondialdehyde (MDA), NOX2-derived peptides, GSH/GSSG ratio, sST2, NT-proBNP, and 8-isoprostanes hold promise in detecting early subclinical cardiac involvement in cirrhosis. Novel antioxidant therapies, including mitochondrial-targeted molecules, NOX inhibitors, and ferroptosis blockers, may improve myocardial remodeling and hemodynamic stability. This review explores the central role of redox imbalance in the cardiohepatic syndrome and its potential utility in diagnosis, monitoring, and therapy.