Sebastian studied Biochemistry at the University of Bayreuth. He received his PhD from Heidelberg University, where he worked on targeting and sorting of membrane proteins by the chloroplast Signal Recognition Particle with Irmi Sinning. For his postdoc he joined the group of Elena Conti at the Max Planck Institute of Biochemistry in Munich. There he combined structural biology with biochemistry to study RNA degradation by the nuclear exosome complex.

From March 2019 Sebastian is a group leader at the Max Perutz Laboratories at University of Vienna.