Walter J. Koroshetz is an American neurologist who served as the director of the National Institute of Neurological Disorders and Stroke (NINDS) from 2015 to 2026. During his tenure, he had leadership roles in several major cross-institute programs at the NIH, including the Brain Research Through Advancing Innovative Neurotechnologies (BRAIN) Initiative, aimed at advancing understanding of the human brain through innovative biotechnologies.
In 2026, Koroshetz was ousted from NINDS, prompting concern in the medical community about the instability and politicization of the National Institutes of Health (NIH) under the second Trump administration.
Koroshetz has said that his interest in the brain began in the eighth or ninth grade after reading about neurotransmitters and ion channels in a book on psychiatry. He was also influenced by seeing his father's six-month hospitalization due to GuillainâÂÂBarré syndrome, a rare autoimmune neurological disease.
Starting in 1971, Koroshetz attended Georgetown University as an undergraduate. During two of the summers, he worked in the laboratory of Jorge Fischbarg, a physiologist at Columbia University. There, he studied neurotransmitters and ion channels, an interest he continued to pursue at the University of Chicago's Pritzker School of Medicine.
Koroshetz began his residency at the University of Chicago in internal medicine. During his second year, he read a paper by C. Miller Fisher, a Canadian-born neurologist, and decided to move to the Massachusetts General Hospital (MGH), where Fisher worked. He completed a second residency there, this time in neurology, followed by postdoctoral studies in cellular neurophysiology. He also did postdoctoral studies in neurobiology at Harvard Medical School.
Koroshetz was a professor of neurology at Harvard Medical School and vice chair of neurology at . He also directed stroke and neurointensive care, and he led resident training at MGH from 1990 to 2007.
In 2007, Koroshetz joined NINDS as deputy director, and in October 2014, he became the acting director. During his deputy directorship and acting directorship, he played a significant role in the creation of NIH StrokeNet, a clinical trial network that streamlines the process of running large clinical trials across many hospitals. He also played a large role in the creation of the NIH Office of Emergency Research. He co-chaired the Brain Research Through Advancing Innovative Neurotechnologies (BRAIN) Initiative, a collaborative, public-private research initiative which is aimed at advancing understanding of the human brain through the development of innovative biotechnologies. Koroshetz has described the initiative, which also aims to help researchers uncover the neurological causes of brain disorders like depression, as "merging the fields of neurology and psychiatry."
In June 2015, the NIH named Koroshetz permanent director of NINDS. During his time at NINDS, he held leadership roles in initiatives supporting research in many areas, including addiction, chronic pain, ALS, traumatic brain injuries, long COVID, undiagnosed diseases, and somatic gene editing.
At the end of Koroshetz's second five-year term, an NIH review panel recommended his reappointment, and NIH director Jay Bhattacharya gave his endorsement. Despite this, under the second Trump administration, the NIH allowed his contract to end on January 24, 2026. As a result, 40 neuroscience organizations, led by the American Academy of Neurology, sent a joint letter to members of Congress expressing "significant concern" and urging Congress to exercise closer oversight over leadership changes.
In 2026, Koroshetz became a senior advisor for the Dana Foundation, a philanthropic organization with a focus on neuroscience.