Introduction Recent clinical trials have demonstrated that increasing physical activity among patients at risk for diabetes can prevent or delay the onset of type 2 diabetes. In this study, we surveyed primary care patients at risk for diabetes to 1) describe physical activity habits, supports, and barriers; 2) identify characteristics associated with increased physical activity; and 3) develop and assess the psychometric properties of an instrument that measures influences on physical activity. Methods A cross-sectional sample of 522 high-risk adults who attended 14 North Carolina primary care family practices were mailed a survey about physical activity and supports of and barriers to physical activity. Risk status was determined by the American Diabetes Association's diabetes risk test. Exploratory principal components factor analyses were conducted on the influences on physical activity instrument. Predictive logistic regression models were used for the dichotomous outcome, meeting recommended Healthy People 2010 activity levels. Results Of the 258 respondents (56% response rate), 56% reported at least 150 minutes of moderate or vigorous activity per week. Higher education remained a significant demographic predictor of activity (odds ratio [OR], 1.72; 95% confidence interval [CI], 1.08–2.75). Participants were less likely to be physically active if they reported that activity is a low priority (OR, 0.45; 95% CI, 0.23–0.89), were worried about injury (OR, 0.42; 95% CI, 0.25–0.69), or had difficulty finding time for activity (OR, 0.38; 95% CI, 0.17–0.87). Conclusion Participants at risk for diabetes who prioritize physical activity, make time for activity, and are less worried about injury have higher odds of being physically active. Primary care practice and community interventions should consider targeting these areas of success to increase physical activity in sedentary individuals at risk for diabetes.