Alain Fischer obtained his medical degree (pediatrics) in 1979, he became professor of immunology at Paris Descartes University, then in 1991 director of an INSERM unit "Normal and pathological development of the immune system". He was head of the "Pediatric Immunology and Hematology" unit (UIH) at the Necker Hospital (AP-HP) from 1996 to 2012. In November 2002, he was elected full member of the Academy of Sciences and in 2011 of the Academy of Medicine. He was a member of the National Consultative Ethics Committee from 2003 to 2009. He was the founding director of the Imagine Institute for Genetic Diseases (2007-2016). Alain Fischer was elected as a foreign member of the U.S. National Academy of Medicine in 2017 and of the U.S. Academy of Sciences in 2019. Alain Fischer is an emeritus professor at the Collège de France, Chair of Experimental Medicine. He is President of the strategic committee on the french vaccination programme against Covid 2020-present)

His work has been recognized by numerous awards, including the Jeantet Prize (2001), the INSERM Grand Prix (2008), the Robert Koch Prize (2014), the Japan Prize (2015).

Alain Fischer's work has been devoted to the study of the human immune system through the characterization of numerous genetic defects and the understanding of their physiopathology. He is the pioneer of gene therapy since 1999.