Newborn screening is a foundational public health program designed to enable early identification and management of treatable genetic, metabolic, and congenital conditions. Because screening technologies expand, including the integration of genomic approaches, attention must shift from detection alone to the effectiveness of the systems that support families following an abnormal screen. This review examines newborn screening as a longitudinal public health system encompassing screening, diagnostic confirmation, communication, genetic counseling, coordinated clinical care, and long-term follow-up.