Cardiovascular disease (CVD) remains the leading cause of global mortality, yet growing evidence shows that psychological processes play a central role in its development and progression. This review synthesizes research on negative psychological states (stress, depression, anxiety) and positive well-being (optimism, emotional vitality) in relation to cardiovascular outcomes. Negative states increase risk through autonomic imbalance, HPA axis dysregulation, inflammation, and maladaptive health behaviors, whereas positive well-being exerts protective effects. Heart rate variability (HRV) is highlighted as a key biomarker linking emotional regulation with cardiac function. Across the lifespan, psychological factors contribute cumulatively to cardiovascular vulnerability. Emerging interventions, including CBT, mindfulness, and HRV biofeedback, show promise in improving outcomes. Overall, the findings support a biopsychosocial framework, emphasizing the need to integrate psychological care into cardiovascular prevention and treatment.