What happens to a person who speaks out about corruption in their organization, and finds themselves excluded from their profession? In this article, I argue that whistleblowers experience exclusions because they have engaged in ‘impossible speech’, that is, a speech act considered to be unacceptable or illegitimate. Drawing on Butler’s theories of recognition and censorship, I show how norms of acceptable speech working through recruitment practices, alongside the actions of colleagues, can regulate subject positions and ultimately ‘un-do’ whistleblowers. In turn, they construct boundaries against ‘unethical’ others who have not spoken out. Based on in-depth empirical research on financial sector whistleblowers, the article departs from existing literature that depicts the excluded whistleblower as a passive victim – a hollow stereotype. It contributes to organization studies in a number of ways. To debates on Butler’s recognition-based critique of subjectivity in organizations, it yields a performative ontology of excluded whistleblower subjects, in which they are both ‘derealized’ by powerful norms, and compelled into ongoing and ambivalent negotiations with self and other. These insights contribute to a theory of subjective derealization in instances of ‘impossible speech’, which provides a more nuanced conception of excluded organizational subjects, including blacklisted whistleblowers, than previously available.