In 2016, nearly a quarter-million women were diagnosed with invasive breast cancer, the second deadliest cancer type. Lifestyle behaviors are well-established risk factors for both the development of, and negative outcomes from, breast cancer. New findings demonstrate that engaging in even minimal amounts of exercise is protective against breast cancer. Further, numerous studies have identified the role of exercise in the treatment of breast cancer and improvement in treatment side effects, quality of life, and overall survival. Unfortunately, few patients are physically active due to multiple barriers. Physicians may be helpful in engaging patients in being more active. Further research is necessary to identify programs and approaches to help patients both with, and at-risk for, breast cancer to engage in exercise.