Although the literature on affect (i.e., the extent to which an individual subjectively experiences feelings and emotions) is burgeoning in the field of entrepreneurship, affect has not received sufficient attention with respect to an important antecedent to entrepreneurial success—entrepreneurial orientation. In this paper, we investigate the role of both positive and negative affect in entrepreneurial orientation (i.e., the strategic posture of a firm/individual with respect to innovativeness, proactiveness, and risk taking) and entrepreneurial success. The results of our analysis, based on two samples (337 Dutch sole proprietors and 254 French small business owners), show that positive affect is positively associated with entrepreneurial orientation, whereas negative affect is negatively associated with entrepreneurial orientation for sole proprietors. With respect to entrepreneurial success, results are mixed. The present study contributes to the understanding of the role of affect in entrepreneurial orientation. It also contributes to the literature on entrepreneurial success, the ultimate objective in the field of entrepreneurship.