Interpreting Nietzsche’s writings on agency and responsibility through the lens of non-sovereignty generates interpretive and political-theoretical contributions. More specifically, I advance three arguments. First, Nietzsche’s genealogical critique of moral responsibility denaturalizes modernity’s conception of individual sovereignty and responsibility, by providing a naturalistic account of agency. Agency and responsibility are neither Kantian presuppositions of practical reason nor pieces of folk psychology to be abolished, but are normative, social, and historical achievements, and thus non-sovereign. Second, this implies a theory of responsibility that is simultaneously more and less demanding than moralistic accounts: while, because agents are not autonomous, they do not bear sole responsibility for their lives, they are called upon to be responsible to and for the world, by maintaining the conditions of possible agency and flourishing. Third, Nietzsche provides both generative resources and cautionary tales for political theories of non-sovereign agency. While non-sovereign responsibility holds emancipatory and potentially democratic implications, Nietzsche’s explicit political writings demonstrate the risk that, rather than tempering existential resentment, this account could generate and intensify a resentful anti-political authoritarianism. Just as non-sovereignty provides a useful framework for making sense of tensions within Nietzsche’s thought, Nietzsche’s post-moral theory of agency and responsibility brings forward tensions, provocations, and paradoxes that must be engaged by theorists of non-sovereignty.