He is the creator and head of the department of medical genetics at the Necker-Enfants malades hospital in Paris.
After a doctorate in medicine (1979) and a science thesis (1988) at the Institut Cochin in the U129 unit then headed by Axel Kahn, he was appointed Professor of Genetics at the University of Paris-Descartes in 1989.
He has been head of the Inserm unit "Genetic handicaps of the child" since 1990, succeeding Jean Frézal, where he had done his clinic (1986-1990) at the Necker Hospital in Paris.
He is the co-founder and current president of the Imagine Institute of Genetic Diseases[3] and a member of the Scientific Council of the AMMi Association.
A 2021 publication found Munnich to be a central researcher for describing rare genetic diseases.