This chapter argues that the United Nations Operation in the Congo (ONUC) leadership employed their access to Congolese political and infrastructural departments to construct an informal trusteeship. It demonstrates the state-building opportunism, imperial aspirations, and administrative power of UN peacekeeping officials deployed to Congo, shortly following decolonization. Following a violent mutiny and uprising in early July 1960, the Congo conflict swiftly expanded to global proportions as European imperial economic interests threatened to destabilize the unity of the newly independent nation. In response to the escalating violence, the UN Security Council authorized the peacekeeping mission on July 14, 1960, at the request of the two Congolese leaders, Patrice Lumumba and Joseph Kasavubu, to restore law and order. The mission’s administrative mandate provided a legitimizing guise for the UN leadership’s state-building strategy on the ground, thus depoliticizing the ONUC leadership’s efforts to control the political direction of the state. ONUC leadership experimented with the functions and permissions of a peacekeeping mission, building upon the practices of past UN trusteeships and perpetuated racial hierarchies within the post-colonial international order. Thus, this chapter traces the longer legacies of colonialism, racism, and liberal paternalism in the politics and practices of UN interventionism and global governance during the decolonizing period.