Christian studied chemistry in Freiburg and Madison/Wisconsin (M.Sc. with Prof. Sam Gellman) and performed his doctoral studies at the RTWH Aachen with Prof. Carsten Bolm. After a postdoctoral stay at MIT with Prof. Barbara Imperiali, he founded his own research group at the Freie Universität Berlin in 2005 as an Emmy Noether fellow. In 2012, he was appointed as Leibniz-Humboldt Professor and Department Head for Chemical Biology at the Leibniz-Research Institute for Molecular Pharmacology (FMP Berlin) and the Humboldt Universität zu Berlin.

His group develops highly selective chemical and chemoenzymatic strategies to functionalize proteins and antibodies to generate protein-based therapeutics against cancer, Alzheimer and viral infections. In addition, he pioneered the development of cell-permeable antibodies for intracellular targeting. He is a co-founder of the Munich-based company Tubulis, which engineers better tolerable cancer drugs, especially antibody-drug conjugates (ADCs), using conjugation technologies from his lab, in particular the P5-labeling platform. Recent awards include the Leonidas Zervas Award (2018), the Astra Zeneca Award from the RSC (2023) and the Max Bergmann Medal (2024). In 2020, he was the first recipient of the Falling Walls breakthrough of the year award in the Life Sciences, recognizing his contributions to develop next-generation biopharmaceuticals.