David Cornwell was born and raised in a small farm town near Salem, in Woodburn, Oregon. He attended South Oregon College in Ashland, Oregon, where he studied general science. He finished his coursework early and spent a semester in Japan as an exchange student. He then went to Northwestern University Dental School and graduated in 1978. Right after graduation, he moved to Massachusetts and opened up his own dental practice. Dr. Cornwell moved his practice in 1986 to its present location in Danvers and named it Chestnut Green Dental.

During the past 25 years since graduation from dental school Dr. Cornwell has taken a tremendous number of continuing education courses, particularly in cosmetic dentistry, implant dentistry, and lasers. He is a member of the American Dental Association, the Massachusetts Dental Society, the World Congress of Microdentistry, the Academy of General Dentistry, the Academy of Laser Dentistry, and the International Congress of Implants.