Background: Postural control and attentional focus are closely interrelated in the regulation of visuomotor performance. The Quiet Eye (QE) period, reflecting optimal attentional control, is known to be influenced by postural stability, yet the underlying neurophysiological mechanisms remain unclear. Purpose: This study examined the effects of balance training on dart-throwing performance, QE duration, and cortical activation to clarify the causal relationship between postural control and attentional regulation. Research Design: A randomized controlled design was implemented, consisting of pre-test, acquisition, retention, and transfer phases. Study Sample: Thirty college students (age: balance training group = 21.2 ± 0.86 years; control group = 21.0 ± 0.96 years) with minimal dart-throwing experience were randomly assigned to either the balance training or control group. Analysis: Performance scores, QE duration (via eye tracking), and EEG alpha power in frontal and temporal regions were analyzed using repeated-measures ANOVA. Results: No group differences were observed at pre-test or during acquisition; however, significant improvements in dart accuracy were found in the balance training group during the retention and transfer tests (p = .001). QE duration significantly increased in the balance training group from pre-test to both retention and transfer (p < .001), while no such change occurred in the control group. EEG results revealed significant group × phase interactions, particularly in the temporal regions (T3, T4, T6), indicating differential modulation of alpha power between groups across learning phases. Conclusions: Balance training enhanced motor performance and attentional control by increasing QE duration and altering cortical activity associated with visuomotor regulation. These findings support a causal pathway in which improved postural stability facilitates attentional efficiency, leading to enhanced motor learning. Integrating balance-based postural training with QE-focused interventions may promote more effective skill acquisition strategies.