What happens when struggling rebels acquire external support? This paper argues that changes in militants’ access to external funding or non-lethal aid create cleavages within rebel organizations by producing a “generational effect” in longitudinal recruitment, cohesion-building, and promotion trends. Specifically, variations in the amount, type, or source of external support affect the scope of recruitment drives and the potential for bureaucratic expansion and employment of non-fighters. Focusing longitudinally on Fateh in Lebanon following 1982, this paper shows how shifts in rebel finance produced competing intra-organizational coalitions in three ways: they drew a line between battle-seasoned volunteers and fresh, financially-backed recruits; they separated those willing to accept external funders’ demands from those who would not; and, they produced schisms between ground troops and top brass, to name a few options. I argue that within Fateh, these generational effects alienated a seasoned old guard from newly minted bureaucrats and well-compensated rebel leaderships, disrupting the organizations’ overall unity and creating uneven patterns of unit-level solidarity. The resulting internal schisms, in turn, affect long-term command-and-control, secondary unit cohesion, intra-organizational violence, and patronage distribution within the organization. To elucidate these processes, this paper draws on 19 months of ethnographic and archival fieldwork among over a dozen Palestinian militant organizations in Lebanon. In particular, it combines in-depth interviews with current and former members of Fateh with nine months of focused organizational ethnography to evaluate the long-term relationship between variance in violence, external funding, and intra-organizational cleavage structure. It demonstrates, in particular, the ways in which different generational cohorts within Fateh developed their own sub-organizational identities, cultures, and practices, creating networks of gossip, protection, favor exchange, and “die hard” behavior that superseded formal organizational hierarchies and challenged leadership control of intra-factional coalitions. Expanding from the focal case, the paper later suggests ways in which lessons from Fateh’s experience can inform research on ongoing and interwoven processes of violence, rebel meaning-making practices, and political outcomes in Libya and Syria. By demonstrating the uneven intra-organizational impact of external material support and by emphasizing intra-organizational politics, this paper challenges existing arguments that associate violent rebel behavior with external funding and lack of cohesion. On a broader level, it also emphasizes the unforeseen consequences of nonlethal foreign interventions in civil wars.