Leptin is a protein hormone primarily synthesized and secreted by adipocytes. It exerts various physiological functions, including appetite suppression, regulation of energy metabolism, promotion of lipolysis, and modulation of inflammatory responses, through its interaction with leptin receptors. In recent years, extensive research has demonstrated that leptin plays a critical role in the occurrence and progression of various cardiovascular diseases (CVDs), including heart failure, myocardial infarction, atherosclerosis, vascular calcification, and hypertension, making it a significant target in CVD research. This review focuses on the molecular biological characteristics of leptin and recent advances in its regulatory mechanisms in several common CVDs, aiming to provide a theoretical basis for research on obesity-associated cardiovascular metabolic diseases.