Background: The importance of physical activity as a modifiable risk factor for stroke in particular and cardiovascular disease in general is well documented. The effect of exercise on stroke severity and stroke outcomes is less clear. This study aimed to assess that effect. Methods: Data collected for patients enrolled in the Ischemic Stroke Genetics Study were reviewed for prestroke self-reported levels of activity and four measures of stroke outcome assessed at enrolment and approximately 3 months after enrolment. Logistic regression was used to assess the association between physical activity and stroke outcomes, unadjusted and adjusted for patient characteristics. Results: A total of 673 patients were enrolled; 50.5% reported aerobic physical activity less than once a week, 28.5% reported aerobic physical activity one to three times weekly, and 21% reported aerobic physical activity four times a week or more. Patients with moderate and high levels of physical activity were more likely to have higher Barthel Index (BI) scores at enrolment. A similar association was detected for exercise and good outcomes for the Oxford Handicap Scale (OHS). After 3 months of follow-up, moderate activity was still associated with a high BI score. No significant association was detected for activity and the OHS or Glasgow Outcome Scale at followup after adjustment for patient characteristics. Conclusions: Higher levels of self-reported prestroke physical activity may be associated with functional advantages after stroke. Our findings should be seen as exploratory, requiring confirmation, ideally in a longitudinal study of exercise in an older population.