He received his PhD from the Leibniz University Hannover with a dissertation on supersymmetric Matrix Models in 1995.
In 2006, Plefka was awarded a Lichtenberg Professorship of the Volkswagen Foundation in quantum field and string theory at the Institute of Physics at Humboldt University Berlin, becoming Full Professor there in 2011.
In 2014 he held a Visiting Professorship at the Institute for Theoretical Physics at the ETH Zurich.
His research focuses on theoretical high energy and gravitational physics, in particular the AdS/CFT correspondence and hidden symmetries in quantum field theory.
His most influential work is the discovery of a hidden Yangian symmetry of scattering amplitudes in N=4 supersymmetric gauge theory together with Drummond and Henn [1] .