OBJECTIVE The prevalence of acute myocardial infarction (AMI) is increasing in young adults, especially in men. This study aims to compare the characteristics and explore the association between age and clinical outcomes in male adults who first experienced AMI. METHODS A total of 2737 male patients with AMI were divided into three groups by age: <50, 50-65, and ≥65 years. Clinical characteristics and long-term results (all-cause and cardiac deaths, nonfatal MI, revascularization, nonfatal stroke, cardiac rehospitalization) were identified across different age subgroups. The association between age and the outcomes was assessed by Cox proportional hazard models. RESULTS This population was followed up for a median of 36.7 months. Patients <50 years had a lower prevalence of diabetes (19.4%) and previous stroke (1.8%), while they were more often to be smokers (77.1%), obese (26%), dyslipidemia (74.7%), and with the single-vessel disease (16.2%). The risk of cardiovascular and all-cause death in patients ≥65 years was higher than patients <50 years, which was noticed through competing risk regression analysis after adjusting for confounding factors (adjusted HR 3.24; 95% CI 2.26-4.22, p=0.020 for cardiovascular death, adjusted HR 4.17; 95% CI 1.91-9.10, p<0.001 for all-cause death). CONCLUSIONS In conclusion, although men who suffered from first AMI under the age of 50 had lower mortality, they had a higher burden of modifiable traditional risk factors. The management of modifiable lifestyles should be addressed to all young AMI patients.