Affect has been theoretically important to charismatic leadership for over 80 years as Weber (1920) referred to the emotion, passion, and devotion that ensue from charismatic authority, and is still evident in modern theories of charismatic and transformational leadership. When leaders express positive affect, they elicit more positive follower attributions of leadership (Lewis, 2000; Newcombe & Askanasy, 2002) and better follower performance (George, 1995; George & Bettenhausen, 1990). Yet the mechanism for these effects has largely been ignored in empirical research. The current studies examine emotional contagion as one means by which leader affect influences follower outcomes. Emotional contagion is the transfer of affect between persons that is thought to occur through unconscious and automatic mechanisms (Hatfield, Cacioppo, & Rapson, 1992). If leaders are able to transmit positive affect to their followers, then followers' positive affect should result in more positive attributions of leadership and better performance. In two laboratory studies and one field study, I tested the effects of affect and emotional contagion on leader and follower outcomes. Study 1 examined the effect of manipulated positive and negative affect on leadership behavior, using MBA students (n = 42). Leaders in the positive affect condition exhibited better leadership behavior than leaders in the negative affect condition. Study 2 tested the subsequent impact of leader affect on follower outcomes (n = 200). The proposed model suggested that leader affect influenced follower attributions of transformational leadership and performance directly, and through follower affect. Structural equation modeling indicated that the hypothesized model fit the data well. Study 3 largely replicated the findings of Study 2, using a field study of principals and teachers ( n = 228). Hierarchical Linear Modeling demonstrated that leader (principal) positive affect related to follower (teacher) positive affect via emotional contagion. Follower positive and negative affect related to follower attributions of transformational leadership and performance, in terms of organizational citizenship behavior. Follower attributions of transformational leadership also related to follower organizational citizenship behavior. As a whole, these three studies highlight the importance of affect and emotional contagion in leadership.