Dr. Walsh completed his MD and PhD degrees at The University of Chicago, neurology residency and chief residency at Massachusetts General Hospital, and postdoctoral training in Genetics with Professor Connie Cepko at Harvard Medical School. In 1993 he became Assistant Professor of Neurology at Harvard and Beth Israel-Deaconess Medical Center, and was promoted to Bullard Professor of Neurology in 1999. In 2002 he was appointed an Investigator of the Howard Hughes Medical Institute. From 2003-2007 he served as Director of the Harvard-MIT Combined MD-PhD training program. He moved to Boston Children’s Hospital in 2006, becoming Chief of Genetics, which in 2014 merged with the Program in Genomics to become the Division of Genetics and Genomics.  The Division contains more than thirty full-time faculty members, roughly evenly divided between clinicians treating children with rare genetic disease, and researchers studying the genetic causes of human illness.

Dr. Walsh’s research has focused on the development and function of the human cerebral cortex, pioneering the analysis of genetic diseases that affect the developing brain, resulting in epilepsy, intellectual disability, autism spectrum disorders, and other conditions. His lab has identified more than three dozen neurological disease genes by establishing world-wide collaborations, and pioneering the analysis of recessive brain disorders in countries, especially in the Middle East, where marriage between distant relatives is common. He has described how a few disease genes essential for constructing the brain were also important targets of the evolutionary processes that shaped the human brain, resulting in the founding of the Allen Discovery Center for Human Brain Evolution in 2017. Recent work has pioneered the understanding of clonal somatic mutations as important causes of human focal epilepsy and autism, and the remarkable genomic diversity of single neurons in human brain.

Dr. Walsh’s research has been recognized by a Javits Award from the NINDS, the Dreifuss-Penry Epilepsy Award from the American Academy of Neurology, the Derek Denny-Brown and Jacoby Awards from the American Neurological Association, the Clinical Research Award from the American Epilepsy Society, the Pruzhansky Award from the American College of Medical Genetics, the Wilder Penfield Award from the Middle Eastern Medical Assembly, the Cajal Club Discoverer Award, the Perl-Neuroscience Award from the University of North Carolina, the Distinguished Alumni Award from the University of Chicago, and the Gruber Neuroscience Prize in 2021. Dr. Walsh is an elected fellow of the American Association for the Advancement of Sciences, and an elected member of the American Association of Physicians, the National Academy of Medicine, the American Academy of Arts and Sciences, and the National Academy of Sciences.