Engagement of cortical resources in balance control is an indicator of fall risk in older adults where people cannot “walk and talk” at the same time. However, there are few direct measures of cortical activity during balance control, and their relationship to balance and other brain functions is unclear. I will show that various electroencephalography (EEG) measures of cortical activity during reactive balance stratify healthy young and older individuals without clinically identifiable impairment across perceptual, cognitive and motor function, identifying possible mechanisms of individual differences in motor ability. Specifically, beta oscillations prior to balance perturbations are strongly associated with perceptual function and associated with motor capacity. Further, evoked cortical potentials due to balance perturbations localized to supplementary motor area are highly stable electrophysiological signatures across individuals that are associated with cognitive-motor interactions necessary for mobility. Further, these relationships are altered with training, aging, and neurological disorders such as stroke and Parkinson’s disease. The intersections across perceptual, cognitive, and motor domains may help identify complex mechanisms underlying balance function and enable development of mechanistic, precision-medicine efforts aimed at fall prevention.