Walker Luzinski is the half-brother of Baby Luzinski. He is the son of Donald Luzinski and the step-son of Sarah Luzinski. He was portrayed by actor Riley Thomas Stewart. After the baby disappeared, Cuddy was afraid that Walker had something to do with it. His parents agreed that he had been upset ever since the baby had arrived. However, when questioned, Walker denied having anything to do with the baby's disappearance.