William Hastwell Thornton was born on July 19, 1859, in New Richmond, Quebec.

He was a physician. He graduated from McGill University (B.A., 1878; M.D.). He was a member of the Royal College of Surgeons of England, and in 1882, he was elected a Fellow of the Royal College of Physicians of London.

He died on January 2, 1907, in New Richmond, Quebec.