Background: This study explored the interrelation between motor coordination abilities and cognitive functions in older adults, aiming to establish a preliminary diagnostic tool that may facilitate early detection of motor–cognitive decline. Methods: Utilizing a mixed-methods approach, we investigated the efficacy of the Stroop word test in conjunction with various motor coordination measurements to identify markers of cognitive aging in older adults. Results: The analysis revealed significant correlations between asymmetric spatial coordination (AC) and Stroop error effects (SEEs), indicating that better coordination correlates with reduced cognitive errors. Multiple-regression analysis showed that AC, simple reaction time (SRT), and anticipation time (AT) significantly predicted SEE (R2 = 0.635), with AC emerging as the strongest predictor (β = −0.475). These results underscore the significance of asymmetric spatial motor coordination as a predictive factor for executive cognitive abilities affected by aging. We propose a potential tool for individuals to monitor their motor–cognitive health. Conclusions: The findings of this study contribute to the growing body of evidence linking physical coordination to cognitive function, emphasizing the importance of integrated diagnostic approaches in the management of aging-related cognitive impairments.