Less than half of US adults and two-thirds of US high school students do not meet current US guidelines for physical activity. We examined which factors promoted physicians' and medical students' confidence in counseling patients about physical activity. We established an online exercise survey targeting attending physicians, resident and fellow physicians, and medical students to determine their current level of physical activity and confidence in counseling patients about physical activity. We compared their personal level of physical activity with the 2008 Physical Activity Guidelines of the US Department of Health and Human Services (USDHHS). We administered a survey in 2009 and 2010 that used the short form of the International Physical Activity Questionnaire. A total of 1,949 individuals responded to the survey, of whom 1,751 (i.e., 566 attending physicians, 138 fellow physicians, 806 resident physicians, and 215 medical students) were included in this analysis. After adjusting for their BMI, the odds that physicians and medical students who met USDHHS guidelines for vigorous activity would express confidence in their ability to provide exercise counseling were more than twice that of physicians who did not meet these guidelines. Individuals who were overweight were less likely to be confident than those with normal BMI, after adjusting for whether they met the vigorous exercise guidelines. Physicians with obesity were even less likely to express confidence in regards to exercise counseling. We conclude that physicians and medical students who had a normal BMI and met vigorous USDHHS guidelines were more likely to feel confident about counseling their patients about physical activity. Our findings suggest that graduate medical school education should focus on health promotion in their students, as this will likely lead to improved health behaviors in their students' patient populations.