Social policy scholars seeking to understand the dynamics of social protection arrangements have advocated for an actor-centric approach. However, when seeking to understand the impact of colonialism on social policymaking, most scholars have focused not on actors but on ideas and institutions. To address this gap, this paper develops an actor-centric framework for understanding the introduction of social policies in colonial contexts. We identify and compare actor constellations of relevance to the introduction of social policies in two colonies of French West Africa that differ with respect to precolonial population density: Dahomey (present-day Benin), with a relatively high precolonial population density, and Côte d’Ivoire, with a relatively low precolonial population density. Despite evidence that precolonial population density can shape colonial strategies and policies, the results provide no supporting evidence that precolonial population density is a driver of meaningful variation in the introduction of social policies or in the composition of the actor constellations from which they originate. Instead, the results point to the key role of transnational and regional actors in the introduction of social policies in colonial contexts. They also highlight the domestic economic and societal arenas as sites where: i) heterogeneity emerges in the social policy actor constellations; and ii) local actors mediate tensions arising from imperially driven social transformations.