We provide an integrative review of the empirical literature on leadership and affect (emotion, mood, and affective dispositions), which is first and foremost a literature on leader displays of affect. We conclude that the influence of leader affective displays can be understood through the mediation paths of emotional contagion and cognitive interpretation of affect in combination with the first- and second-stage moderators of these paths. We also conclude that the common yet overly simplistic notion that leader displays of positive affect are more effective than leader displays of negative affect can in important part be attributed to an overreliance on subjective ratings as indicators of leadership effectiveness, whereas behavioral indicators of leadership effectiveness suggest a more contingent view of the effectiveness of positive and negative affective displays. We propose that to bolster and further develop these conclusions, we need (a) more research focusing on moderation in dual-path mediation; (b) development of theory about cognitive interpretations following leader affective displays; and (c) more sophisticated models of the difference amongst different affective states to better capture the complexity of their effects. We also outline how evidence regarding the role of follower affect in response to leadership more generally points to the potential for integration of affective and non-affective models of leadership.