Background: The Montreal Cognitive Assessment (MoCA) is a cognitive screening tool known to accurately measure mild cognitive impairment (MCI) in many different neurological populations. Objective: We aimed to determine whether a sport-related concussion (SRC) history and other concussion modifiers influence global cognitive function in high-performance athletes. Methods: A cross-sectional study of 326 varsity and national team athletes aged 18–36 years was completed at the University of Calgary Sports Medicine Clinic, Calgary, Alberta, Canada. Logistic regression analysis was used to examine the association between the total MoCA score, MoCA subscales, and number of previous SRC, adjusting for age, sex, sport participation (SP), and concussion modifiers. Results: Athletes with a history of three or more SRC were 5.36 times more likely to score less than 26/30 on the MoCA (the cutoff for MCI) compared to athletes with two or less SRC (p = 0.02). Males were 2.23 times more likely to have MCI than females (p = 0.0004). There was a significant relationship between the number of previous concussions and the MoCA subscales of attention (p = 0.05) and abstraction (p = 0.003). Age, SP, and concussion modifiers (migraine, depression, anxiety, and attention deficit and hyperactivity disorder) did not influence the relationship between MoCA and previous concussion history. Conclusion: In the appropriate clinical context, cognitive screening with the MoCA may benefit clinical care in athletes with multiple previous SRC, but should not replace a full neuropsychological assessment. Thus, further research is needed to compare the MoCA to full neuropsychological assessments in this population.