We explore how formal managers' centralities in both positive and negative networks predict followers' perceptions of their leadership. By incorporating social networks and social ledger theory with implicit leadership theories (ILTs), we hypothesize that formally assigned group leaders (managers) who have more positive advice ties and fewer negative avoidance ties are more likely to be recognized as leaders by their followers. Further, we posit that managers' informal networks bring them greater social power, an important attribute differentiating leaders from non-leaders. We conducted two survey-based studies in student and field teams to test the hypotheses. Based on nested data in both studies, we found support for our hypotheses. These results remain robust across the two studies even though they used different designs (cross-sectional versus longitudinal), different samples (field versus students) across different countries (United States versus India), and a host of control variables at both the leader and follower levels. We find that managers who are central in the advice network are socially powerful and are seen as leaders by individual followers. In contrast, managers who are avoided by followers lack informal social power are not seen as leaders. We conclude by discussing the theoretical and practical implications of our findings and the ways in which our theory and results extend ILTs and social network theory.