In Richard Feynman’s work of the late 1940s the virtual particle came to the fore and took centre stage. Following Feynman’s approach to quantum electrodynamics and his quite idiosyncratic methods and conceptions reveals the diverse modifications the concept of the virtual particle underwent in the course of the reconfiguration of quantum electrodynamics. Freeman Dyson’s systematization of Feynman’s approach did not only bring Feynman diagrams to the masses, but in the discussion between Feynman and Dyson a “false prediction” of the diagrammatic format occurred. All the same, the virtual particle became ever more prominent and for Feynman himself took centre stage. We can understand this observation in a historio-philosophical way: When the exemplar, the paradigmatic problem of the theory, changed in the late 1940s one of the most important concepts of the practice of theory, i.e. the virtual particle, changed in its properties and its status.