ST-elevation myocardial infarction (STEMI) requires rapid reperfusion to limit myocardial injury. Primary percutaneous coronary intervention (PPCI) is the preferred reperfusion strategy when it can be delivered within the recommended time, and door-to-balloon (DTB) time is an important indicator of emergency cardiac care performance. Quality of life after PPCI is also an important patient-centred outcome. This study examined the relationship between DTB time and quality of life in patients with STEMI after PPCI and identified clinical factors associated with quality of life. A quantitative observational analytic study with a cross-sectional design was conducted among 142 patients with STEMI who underwent PPCI at the National Cardiovascular Center Harapan Kita Hospital, Jakarta. Participants were selected purposively and comprised 71 patients in the on-time group and 71 in the delayed group. Quality of life was assessed using the Indonesian version of the Seattle Angina Questionnaire-7 (SAQ-7), a validated instrument with good construct validity and test–retest reliability (ICC ≥0.78). Univariate and bivariate analyses were followed by binary logistic regression. Statistical significance was set at p<0.05. The mean DTB time was 73.85 minutes in the on-time group and 142.54 minutes in the delayed group. Overall, 93 participants (65.5%) had good quality of life. The proportion with good quality of life was 78.9% in the on-time group and 52.1% in the delayed group (p=0.001). Bivariate analysis also showed significant associations for comorbidity burden (p=0.023), left ventricular ejection fraction (LVEF) (p=0.020), physical limitation (p<0.001), and angina frequency (p<0.001). In the final multivariable model, DTB (OR=2.794; 95% CI: 1.215–6.426; p=0.016), LVEF (OR=2.342; 95% CI: 1.064–5.154; p=0.034), and length of stay (OR=1.213; 95% CI: 1.030–1.429; p=0.021) were significantly associated with quality of life. Quality of life after STEMI and PPCI was associated with timely reperfusion, ventricular systolic function, and length of hospital stay. Strengthening rapid STEMI pathways and monitoring functional recovery may support better patient-reported outcomes.