Entrepreneurship and strategic management are both concerned with growth and wealth creation (Hitt & Ireland, 2000; Hitt, Ireland, Camp & Sexton, 2001). Although both fields have developed largely independently, they both aim at explaining how firms adapt to environmental change and exploit opportunities (Venkatraman and Sarasvathy, 2001). Strategic entrepreneurship reflects both entrepreneurial opportunity-seeking actions and strategic advantage-seeking actions (McGrath and MacMillan, 2000; Hitt and Ireland, 2000). Top management teams (TMT) are critically important for exercising strategic entrepreneurship. They have the final responsibility for selecting the firm’s strategies (Hambrick and Mason, 1984). Particularly in start-up firms, the influence of top management teams on strategic directions and eventually on their firm performance is especially significant (West & Meyer, 1998). Despite scholars recognize the importance of both strategic entrepreneurship and top management team influence in understanding the performance of start-up firms, little empirical work has combined both views. In this paper we examine the relative impact of top management team characteristics on the relationship between strategic entrepreneurial behavior and start-up firm performance.