This is one of the first studies to examine the "educational entrepreneur" in K-12 public schools and the first to present an instrument designed to measure entrepreneurial thinking among teachers using a type of reasoning, effectual reasoning, which has been proposed in the business literature on entrepreneurs. This study situates entrepreneurial thinking within the K-12 education arena and examines the relationship between high school and middle school teachers' use of effectual reasoning and their corresponding implementation of high, medium, or low levels of innovation in STEM areas within their classrooms, districts, or across districts. Our findings correlated higher use of effectual reasoning, a component of entrepreneurial thinking, with higher levels of implementation of innovations among teachers within an NSF [National Science Foundation] grant, Entrepreneurial Leadership in STEM Teaching and learning, which centered on deeper content, reform-oriented pedagogies, and entrepreneurial thinking. We found that high innovators viewed "uncertainty" differently than low innovators by associating it with more positive cognitive structures and that innovators at different levels hold distinct notions of what constitutes high and low risk innovations. Contrary to the common notion that entrepreneurs are high-risk takers, results reveal that the types of innovations perceived by high innovators as low risk are viewed as high risk by low innovators. Furthermore, the results are consistent with the idea that entrepreneurs do certain types of things to lower/manage the risk of innovations before and, if necessary, during the implementation of an innovation.