South Africa’s post-1994 leadership in multilateral forums and its efforts to be a bridge-builder and norm-entrepreneur in the international arena, have earned it the label of ‘middle power’. The label itself is contentious, as there is no commonly accepted definition of middle powers and there is disagreement about whether the label applies to South Africa. This study contributes to the discourse on a new normative ‘middle’ in the realm of structural power, by using the case of South Africa’s two terms as a non-permanent member of the United Nations Security Council (2007 - 2008 and 2011 - 2012). The Council represents the most powerful forum of global structural power, and therefore offers a useful and compact arena in which to analyse South Africa’s participation from a middle power perspective. The original contribution of the study is, on the one hand, its approach from a hitherto under-researched global South perspective, and on the other hand its purposeful analytical nexus between theory and practice in international relations. In doing so, the refinement and development of an important theoretical construct – the ‘middle power’ idea as related to the distinct diplomacy of certain emerging powers – is supported by a critical understanding of an actual case of state (South Africa’s) behaviour in the contemporary realm of structural power.