Early brain network development lays the foundation for many lifelong neurocognitive functions. Major structural and functional networks emerge during the pre- and perinatal periods, and their self-organization critically depends on the brain’s endogenous activity. Understanding these early wiring processes is essential for guiding timely interventions and improving neurodevelopmental outcomes. Electroencephalography (EEG) is a widely used clinical method for recording whole-brain electrical activity in infants and assessing the developmental dynamics of neuronal networks. This talk will present analytical approaches to characterize infant EEG-based functional networks across distinct brain rhythms, vigilance states, and coupling modes. It will then discuss key organizational principles of infant brain networks and how early-life adversities affect them. Finally, it will provide evidence that specific features of cortical network organization are linked to later neurodevelopmental outcomes, highlighting their potential as early biomarkers of brain function.