Dr. Grayson graduated with a bachelor's degree from Knox College in Galesburg, Illinois before attending the University of Chicago, Pritzker School of Medicine, from which he received his medical degree. After completing an internal medicine residency at the Hospital of the University of Pennsylvania, he undertook his allergy/immunology fellowship at Johns Hopkins University. Dr. Grayson has been on the faculty at Washington University School of Medicine and the Medical College of Wisconsin. In August 2016 Dr. Grayson became director of the Division of Allergy and Immunology and Professor of Pediatrics at Nationwide Children's Hospital and The Ohio State University.
Dr. Grayson oversees a laboratory studying the role viral infections play in the development of allergic disease. He has published over 90 peer-reviewed articles and trained over 14 post-doctoral or clinical research fellows. He is board-certified in allergy and immunology and is an active fellow of the American Academy of Allergy, Asthma, and Immunology (AAAAI), and American College of Allergy, Asthma, and Immunology. Dr. Grayson has been the director of Fight Asthma Milwaukee (FAM) Allies, the Milwaukee asthma consortium, has been on the board of directors for the AAAAI, and is a former co-leader of the Infection, Inflammation, and Immunity Research Unit of the Children's Research Institute of the Children's Hospital of Wisconsin. He is the incoming editor-in-chief of the Annals of Allergy, Asthma, and Immunology, serves on grant review study sections for the National Institutes of Health and is the chair of the American Lung Association's Grant Review Panel B. In addition to being a member of the Scientific Advisory Committee of the American Lung Association, Dr. Grayson is on the board of directors of the Asthma and Allergy Foundation of America and the American Board of Allergy and Immunology (ABAI). Dr. Grayson is an elected member of the Collegium Internationale Allergologicum, the allergy research honorary society, as well as the American Society for Clinical Investigation (physician-scientist honorary society). Dr. Grayson has been named a "Best Doctor in America" every year since 2009. His clinical interests are primarily asthma, allergic rhinitis, food allergy anaphylaxis.