Metabolic dysfunction-associated steatotic liver disease (MASLD) and atrial fibrillation (AF) are two highly prevalent conditions that share overlapping cardiometabolic risk factors, including obesity, type 2 diabetes, hypertension, and dyslipidemia. Growing evidence suggests that these two disease entities are pathophysiologically linked through systemic inflammation, oxidative stress, and structural remodeling. Population-based studies and meta-analyses report an association between steatotic liver disease and both incident and recurrent AF. While several analyses observe persistence of this association after adjustment for cardiometabolic risk factors, residual confounding and limitations of observational designs preclude firm causal inference. Conversely, heart rhythm disturbances may exacerbate hepatic fibrosis and dysfunction. Lifestyle interventions—particularly sustained weight loss—have demonstrated significant benefits in both conditions. Emerging pharmacological options, including incretin mimetics, flozins, statins, and thiazolidinediones, show promise in addressing the liver–heart axis, while appropriate anticoagulation remains essential in AF management. This review summarizes current epidemiological data, mechanistic insights, diagnostic approaches, and therapeutic strategies related to the coexistence of MASLD and AF. Emphasis is placed on shared pathogenic pathways, non-invasive diagnostic tools, and integrated management options.