Jean-Laurent Casanova received his M.D. in 1987 and his Ph.D. in 1992, after training at the Pasteur Institute in Paris and the Ludwig Institute for Cancer Research in Lausanne. He was appointed professor at the Necker–Enfants Malades Hospital in Paris in 1999 and with Laurent Abel, cofounded the Laboratory of Human Genetics of Infectious Diseases. He was appointed professor at Rockefeller University in 2008 and named HHMI investigator in 2014. He continues to partner with Dr. Abel, maintaining their labs in Paris and NY, where they study the human genetic and immunological determinants of life-threatening infectious diseases.

Casanova searches for rare and common single-gene inborn errors of immunity (IEI) that selectively compromise the immunity of otherwise healthy individuals who are vulnerable to specific infectious diseases. He then searches for other causes disrupting the same mechanisms of host defense and thus characterizes the causal mechanisms of life-threatening infectious diseases. Over the past 30 years, Casanova discovered the first monogenic IEI underlying various viral, bacterial, and fungal infections. In response to the SARS-CoV2 Global Pandemic, Casanova cofounded the COVID Human Genetic Effort with Helen Su at the NIAID. He discovered monogenic inborn errors of type I interferon immunity underlying severe forms of COVID-19 in previously healthy individuals. This led to his discovery that pre-existing autoantibodies neutralizing type I interferons account for at least 15% of severe cases. This breakthrough led to the discovery that autoantibodies neutralizing type I IFNs are strong, common, and global determinants of a growing number of severe viral diseases. For example, they underlie 40% of cases of West Nile virus encephalitis.

Casanova has published 788 experimental and clinical papers and 268 editorials, book chapters and reviews to date. He is the recipient of multiple international awards, including the Dautrebande Prize (Belgium, 2004), Richard Lounsbery Award (USA/France, 2008), InBev Baillet-Latour Health Prize (Belgium, 2011), Ilse and Helmut Wachter Foundation Award (Austria, 2012), Robert Koch Award (Germany, 2014), Sanofi-Institut Pasteur Award (France, 2014), Stanley J. Korsmeyer Award (USA, 2016), Inserm Grand Prix (France, 2016), Juan Abarca Prize (Spain, 2021), and the Novo Nordisk Prize (Denmark, 2025). He was elected to EMBO (2005), USA National Academy of Sciences (2015), USA National Academy of Medicine (2015), and Royal Academy of Medicine of Belgium (2021), and received doctorates honoris causa from the University of Zürich (Switzerland, 2009), the University of Debrecen (Hungary, 2010), and the Katholieke Universiteit Leuven (Belgium, 2022)