duction: Myocardial infarction (MI) remains a major cause of morbidity and mortality worldwide, and individuals who survive a first MI are at high risk of recurrent cardiovascular events. Lifestyle modification—including dietary changes, regular physical activity, alcohol and smoking cessation—is a cornerstone of secondary prevention. However, adherence to these recommendations varies widely, and the overall effectiveness of these interventions in real-world post-MI populations requires comprehensive evaluation. This systematic review aims to assess the impact of diet, physical activity, alcohol and smoking cessation on recurrent MI, cardiovascular mortality, hospital readmissions, and quality of life among adults following myocardial infarction. Objectives: This systematic review aims to evaluate the impact of dietary modification, physical activity, smoking and alcohol cessation on cardiovascular outcomes after myocardial infarction, assess adherence rates, and identify their effects on recurrent MI, mortality, hospital readmissions, and factors influencing long-term adherence. Methodology: This systematic review followed PRISMA guidelines. A comprehensive search of PubMed/MEDLINE, Embase, and Scopus was conducted from inception to the most recent date. Eligible study designs comprised randomized controlled trials, cohort, case-control, and cross-sectional studies, and review articles. Non-English articles, studies lacking extractable data, or those without clear outcome measures, editorials, commentaries, and conference abstracts, were excluded. Results: Lifestyle modification is central to secondary prevention after MI. Mediterranean-style diets were associated with reduced cardiovascular events and mortality, though evidence in secondary prevention remains limited. Exercise-based cardiac rehabilitation lowered cardiovascular mortality and hospitalizations and improved functional and psychosocial outcomes. Smoking cessation reduced recurrent events by approximately one-third. Light-to-moderate alcohol intake showed mixed associations with mortality. Conclusion: Effective secondary prevention after MI requires integrated lifestyle modification, cardiac rehabilitation, and optimal risk-factor control. Although these strategies improve survival and psychosocial outcomes, adherence remains suboptimal. Personalized, multidisciplinary, and digitally supported rehabilitation models may enhance long-term cardiovascular outcomes.