Alagille syndrome (AGS) is a highly complex, multisystem, autosomal dominant disorder that is caused by a defect in the Notch signaling pathway. This syndrome mainly affects the liver, causing significant cholestasis, which is caused by a paucity of intrahepatic bile ducts. There can be cardiac involvement, including, but not limited to, pulmonary stenosis and tetralogy of Fallot. Patients can also present with butterfly vertebra, ocular issues, and vascular events. Because this syndrome follows an autosomal dominant inheritance, it can have variable expression even in the same family line. For infants in the NICU who have a cardiac defect and persistent hyperbilirubinemia after two weeks of age, genetic testing for AGS should be considered. Early detection and diagnosis can lead to improved outcomes. In this discussion of AGS, the clinical features as well as management are discussed.