In our age of globalization and complex threat environments, every business is called upon to manage security. This tendency is reflected in the fact that a wide range of businesses increasingly think about security in broad terms and strive to translate national security concerns into corporate speech. This article argues that the profession of the security manager has become central for understanding how the relationship between national and corporate security is currently negotiated. The national security background of most private sector security managers makes the corporate security professional inside the company a powerful hybrid agent. By zooming in on the profession and the practice of national security inside companies, the article raises questions about where to draw the line between corporate security and national security along with the political consequences of the constitution of such boundaries.