This dissertation examines how rebel organizations are affected by their leader’s social capital. In conflict research, leader functions and roles have been diverse, for example solving coordination problems in collective action, or devising ideologies for broad public support. What is missing is relating inter-individual differences to the social context within which these differences are argued to matter. Studying leader-level variation across conflict stages enables the identification of how the abilities of a leader interact with the challenges at hand. Spelling out the social context within which both the leader and the rebel organization are embedded, allows for the identification of the socially conditioned advantages and constraints that produce and restrict the application of human capital. I argue that a rebel leader's social capital influences a rebel organization prior to and during conflict, and when parties consider ending conflict. To investigate the main research question “how are rebel organizations affected by their leader’s social capital”, this study makes use of newly collected data on all rebel leaders from 1946 -- 2023. The results of the analyses suggest that a rebel leader's social capital is correlated with slower conflict onset, less competitors during conflict, and a mixed relationship with the likelihood of negotiation onset. In addition to the empirical contribution, I add to the literature, as I re-consider and statistically examine three central concepts in the conflict literature. I conceptualize and operationalize conflict onset as a process, thus nuancing existing explanations of mobilization dynamics prior to and for the purpose of civil conflict. Second, explain the number of rebel organizations during conflict, or "insurgency cohesion", by highlighting that both types of competitor emergences take place in the same social space. Third, I consider negotiation processes both in their public and secret format and how they relate, thus studying them jointly as is closer to observations.