Coronary artery calcium (CAC) is associated with poor angiographic results and higher rates of complications after percutaneous coronary intervention (PCI). Limited data are available regarding the impact of angiographically evident CAC on long-term outcomes after primary PCI in patients presenting with ST-segment elevation myocardial infarction (STEMI). In this single-center, registry-based retrospective cohort analysis, we analyzed 2,143 consecutive patients presenting with STEMI who underwent primary PCI within 12 hours of symptom onset. Patients were divided based on degree of CAC (determined by visual inspection of angiograms) as follows: (1) moderate-to-severe CAC (n = 306; 14.3%) and (2) minimal-to-none CAC (n = 1,837; 85.7%). The primary end point was all-cause mortality at 1-year after PCI. Patients with moderate-to-severe CAC were older, women, and had higher rates of hypertension, chronic kidney disease, and peripheral vascular disease. Moderate-to-severe CAC was associated with higher rates of anterior myocardial infarction, advanced Killip class, and poor final angiographic results. At 1-year follow-up, rates of all-cause mortality were higher in the moderate-to-severe CAC cohort than those in the minimal-to-none CAC cohort (8.5% vs 4.7%; p = 0.008). However, after accounting for major clinical and angiographic characteristics, moderate-to-severe CAC on presenting STEMI angiogram was no longer predictive of 1-year all-cause mortality. In conclusion, advanced CAC burden occurs in ∼15% of patients undergoing primary PCI for STEMI and reflects a marker of adverse prognosis late into follow-up after PCI.