Since 2000, both emerging powers like China and India and established powers like the EU and the US were voraciously seeking close relations with Africa, and the African Union was playing a coordinating role in managing the ensuing relationships. However, the role of the AU as a collective African norm entrepreneur has not been recognized due to the theoretical limitations imposed by the mainstream theories of IR. This study used ‘Subsidiarity Norm Theory’ to find out collective African agency in the progressively evolving relations using data collected from treaties, policy statements, press releases, other relevant documents, and policy actions. This study found that the AU was emerging as the premier norm entrepreneur in international politics of Africa despite the difficult challenges posed by factors such as limited organizational capacity, the opportunistic actions of some of its members, and interventions by external powers that encroach on its coordinating role. Actions of the AU and consequent intersubjectively evolving relations with emerging powers like China also reveal that the AU was both responding to emerging powers' policy initiatives and constituting the terms of the engagements.