Stephen Cusack, born in London, studied mathematics, physics and theoretical physics as an undergraduate at Cambridge University and obtained a PhD in theoretical solid-state physics at Imperial College, London in 1976. Switching to molecular biology, in 1977 he joined the newly founded laboratory of EMBL at Grenoble as a postdoc to study virus structure using neutron scattering. In 1985, he spent a year learning X-ray crystallography with Don Wiley at Harvard, working on influenza virus hemagglutinin. In 1989, he became Head of EMBL Grenoble, a post he occupied until 2022. Benefitting from the establishment of the ESRF on the Grenoble Campus in the 1990s, he has focussed on using X-ray crystallography, and more recently cryo-electron microscopy, to study protein-RNA systems in gene expression, viral replication and innate immunity. He is best known for his structural analysis of aminoacyl-tRNA synthetases, the anti-viral pattern recognition receptor RIG-I, and his pioneering structural and mechanistic studies of the influenza virus RNA-dependent RNA polymerase, for which he received the Ivano Bertini Award in 2015. Several of his projects evolved a structure-based drug development aspect in collaboration with various pharmaceutical companies and in 2009, he co-founded Savira pharmaceuticals to develop anti-influenza drugs. In 1998, he became a member of the European Molecular Biology Organization and in 2015, he was elected as a member of the Royal Society of London.