Sebastian studied chemistry at the Universities of Hamburg and Lund, focusing on physical chemistry. He pursued his PhD in time-resolved spectroscopy of organic semiconductors at the University of Cambridge. Later, he delved into the study of structural changes in proteins and small molecules at Gothenburg University. There, he developed time-resolved X-ray scattering methods and uncovered several protein structural changes crucial to photoreceptor protein function. As the Karin and Herbert Jacobssons Professor of Biochemistry at the University of Uppsala, his current research explores protein structure and dynamics with increasing precision in time-resolved experiments, thereby bridging structural biology and physical chemistry.