Noonan syndrome is a genetic disorder that can present with a wide range of clinical manifestations, making diagnosis challenging. This article presents the case of a 29-year-old male who presented with chest pain and ST-segment elevation, initially raising suspicion for acute coronary syndrome. However, coronary angiography revealed only ectasia of the coronary arteries, with no other pathological findings. A detailed physical examination and echocardiography revealed a pulmonary murmur, pectus excavatum, and café-au-lait spots. Additionally, both echocardiography and cardiac magnetic resonance imaging (MRI) showed localized left ventricular hypertrophy. Genetic testing identified a heterozygous missense variant in the PTPN11 gene, leading to the diagnosis of Noonan syndrome. This case highlights the importance of thorough physical examination and multimodal imaging in the diagnosis of Noonan syndrome.