In 1852, at the early age of 25, he was elected a Fellow of the Royal Society, and in the following year he obtained the Astley Cooper prize of three hundred guineas for a dissertation "On the structure and Use of Spleen."

He had the good fortune of securing the help of his friend Henry Vandyke Carter, a skilled draughtsman and formerly a demonstrator of anatomy at St. George's Hospital.

The book is still published under the title Gray's Anatomy and widely appreciated as an authoritative textbook for medical students.

He is assumed to have been infected due to his extended and meticulous caring for his ten-year-old nephew, Charles Gray, who did eventually recover.

On 13 June 1861, the day he was to appear for an interview as a final candidate for a prestigious post at the St. George's Hospital, he died at the age of 34.