This article brings Alexander Wendt’s (2015) ‘quantum social ontology’ into the realm of empirical International Relations (IR) research by coupling it with Q methodology. It shows how Wendt’s ontology and Q methodology share a central interest in complex agency and are inherently allied in terms of principles and purposes. The quantum view has catalysed conversation within IR and social sciences more broadly, but that debate has remained almost exclusively on a theoretical level. This article shows that there is potential for empirical research in this area regardless of whether one considers the quantum view to be an analogy or ontological reality. Q methodology’s grounding ideas align with quantum physics and the quantum social ontology, e.g. in the fashion it conceives of subjective states of mind and their measurement. Practical examples of Q methodological work are presented to illustrate the quantum concepts in a social scientific setting. The article argues for a broader study of political subjectivity within IR through a notion of personhood, which opens up vast potentialities for agency as well as for breaking free of determinism, and fixed notions of human nature as well as ostensibly fixed understandings of advantaged or disadvantaged subject positions.