Experience of primary percutaneous coronary intervention (PCI) for young adults with acute myocardial infarction (AMI) due to sequelae of Kawasaki disease (KD) has been extremely limited. In the present report on three young adults (two males and one female; age 20–35 years) with AMI, we performed primary PCI and intravascular ultrasound imaging (IVUS). Case 1 underwent thrombectomy alone in the proximal left circumflex coronary artery, and subsequent IVUS depicted a large aneurysm with an asymmetrically intimal thickening and a residual thrombus in the culprit. Case 2 underwent balloon dilation with adjunctive intracoronary thrombolysis in the proximal left anterior descending coronary artery (LAD), and IVUS during follow-up coronary angiography (CAG) delineated a regressed giant aneurysm with a markedly intimal thickening in the culprit. Case 3, with past history highly suggesting KD, underwent balloon dilation in the proximal LAD, and follow-up CAG as well as IVUS revealed a neoaneurysmal formation in the culprit. In all of the patients, PCI was angiographically effective at the acute phase without complication. Follow-up CAG performed 3–6 months after the procedure revealed no restenosis in all three cases, but a new coronary aneurysm still remained in case 3. Although case 1 and case 2 had no obvious history of KD, the vessel wall morphology from IVUS closely resembled the coronary sequelae after KD, suggesting that they might have antecedent incomplete KD. These cases suggest that primary PCI against coronary sequelae of KD in young AMI patients might be safe and effective in the short term.