The Development of Slaving Societies in the Americas is a comparative history of slaving, slavery, and ethnogenesis that focuses on changes in slaving practices in São Paulo and Carolina between 1614–1715. It illuminates how colonial slavers coopted Native practices of slavery in Brazil in the late sixteenth century and in Carolina in the seventeenth century to create slave trades that trafficked in Native people. This dissertation reveals how Native and colonial figures used slaving as a profitable strategy to create wealth in people as dependents and as commodified, exchangeable trade goods, effectively transforming our understanding of Native peoples lived experiences as captors and captives in colonial borderlands. Through analyses of colonial council records, wills, inventories, and the correspondence of Jesuits, Franciscans, and colonial officials, this work follows those actors who benefitted from slaving and those commodified by it, demonstrating that slaving societies formed based on the slaving strategies employed by colonial and Native actors. As Native slave trades proved profitable and violence spread, Native and colonial slaving led to the coalescence of Native groups through incorporating refugee Natives fleeing slavers and Native slavers themselves. Building on studies of Native slavery in Latin America the project draws on insights from Africanists to move beyond Eurocentric colonial categories of enslavement—free versus unfree. Instead, the dissertation analyzes how the slaving strategies of colonists and Native groups in two borderlands created slaving societies who focused their socio-economic organization and production on the enslavement of Native peoples in the Americas. Through a comparison between the creation of Native and colonial slaving societies in São Paulo and Carolina, this dissertation makes two interventions: one historical, through identifying broader patterns of slaving strategies in the Americas, and another historiographical, by moving beyond nationalistic narratives of slavery, violence, and cross-cultural exchange.