T-Cell Acute Lymphoblastic Leukemia (T-ALL) is commonly diagnosed in adolescents and is a rare diagnosis in children under 12 months of age. There is little guidance regarding the details of management and outcomes for infantile T-ALL, in particular the use of nelarabine in an infant. Additionally, the genomic landscape of this rare oncologic presentation has not been well documented. We present the unique management, genomics, outcomes, and clinical course of a patient with the diagnosis of infantile T-ALL.