Congenital defects of bile acid synthesis are rare disorders that cause progressive liver dysfunction. Prolonged neonatal hyperinsulism (PNH) is a separate entity that leads to persistent hypoglycemia secondary to stress. We present a 4-month-old infant who presented with liver failure secondary to a bile acid synthesis defect. The patient's liver failure resolved with oral cholic acid therapy. This patient also developed PNH, which slowly resolved over time. This case illustrates a possible relationship between cholestatic liver failure and PNH. This relationship may help define specific stressors that increase the likelihood of developing PNH.