© 2023 Global South Ltd.In international relations, hierarchy is generally understood as the relational contract by which two states legitimately acknowledge their superior and subordinate ranks. Empirical studies, however, show that some states experience distinctive hierarchical patterns, such as military intervention and nation-building. This study calls them the ‘informal imposed hierarchy’ (IIH after this) because they all install favoured leaders, governmental structures and/or troops in target states without the consent of the target states’ population. Using state clusters from 1945 to 2003, we found that four sorts of states experienced IIHs: those having counter-hegemonic actors, signalling a move to the rival hierarchy, seeking an exit door from the current hierarchical system, and perceived to present new security risks (e.g. terrorism). IIH likely generates instability since it installs and protects illegitimate rulers in the target state. It can aggravate internal war in subordinate states with single-party governments or heterogeneous communities. In order to assess the model’s and the arguments’ explanatory power, the study selects the relevant universe cases. The next, it examines pre- and post-Soviet eras in Afghanistan and the 2001 and 2003 US invasions of Afghanistan and Iraq as control cases. These cross-cases illustrate the change of IIH’s motives over time and across hierarchies.