Henry Sonneborn graduated from John Hopkins University with a bachelor's degree and went on to receive his medical degree at Albany Medical College. He did his internship and residency at Albany Medical Center Hospital and a hematology oncology fellowship at the University of Utah Medical Center.
He is board certified in Internal Medicine and Medical Oncology. He practices Internal Medicine at the Jackson Gray Medical Building, located at 330 Borthwick Ave, Suite 301, Portsmouth, NH. He practices Hematology and Oncology at Wentworth Douglass Hospital in Dover, NH.