This dissertation addresses two issues in the literature on informal leadership emergence (i.e., the process of an individual without a formal leadership position coming to exert leadership influence over others). First, scholars have focused on situations in which a focal person’s leadership claiming is aligned with a peer’s leadership granting. In doing so, past work has overlooked instances of misalignment, that is, when a focal person claims more leadership than a peer grants (i.e., overclaiming) or when a peer grants more leadership than a focal person claims (i.e., underclaiming). Second, the consensus in the literature suggests that emerging as an informal leader provides more beneficial outcomes to the individual and their team than non-emerging. However, I argue that this assumption may not be warranted in some situations, for example when a focal person’s lack of claiming is aligned with a peer’s lack of granting. Drawing on the leadership identity claiming and granting framework, I postulate four forms of informal leadership (non)emergence, namely (1) dyadic emergent leadership, (2) dyadic leadership absence, (3) overclaiming, and (4) underclaiming. Based on role theory, I then build theory regarding their effects on behavioral consequences through affective and cognitive mechanisms. More precisely, I suggest that forms characterized by congruence in leadership claiming and granting (as opposed to forms characterized by incongruence) result in increased peer backing-up behavior towards the focal person (mediated by enthusiasm and respect) and reduced peer social undermining (mediated by anger and revenge cognitions). I further hypothesize asymmetrical incongruence effects and consider a focal person’s prosocial motivation as a boundary condition. I conducted three studies to examine my theorizing. In Pilot Study 1 (N = 199), I adapted and validated a measure to assess leadership claiming and granting. In Pilot Study 2 (N = 151), I shortened established measures. In the Main Study (N = 279), I tested my theoretical predictions yielding mixed findings. Whereas I find support for the congruence effect on backing-up behavior, all other hypotheses were not supported. I report supplemental analyses to examine these null results and discuss the theoretical, empirical, and practical implications of this research.