He graduated M.D., and ultimately was assigned as keeper of the departments of Natural history and antiquities in the British Museum, which consisted of the collection purchased from Sir Hans Sloane on his death in 1753.
[5] Within zoology, Gray's Catalogue of Shells for the British Museum (1791) best reflect his work as a malacologist.
In 1785 and 1786, Gray delivered Croonian Lectures on topics related to muscle response, and in 1789 he contributed Observations on the … Amphibia to the Philosophical Transactions of the Royal Society, of which he was a fellow (elected Feb. 1779), and of which on St. Andrew's day in 1797 he became the junior secretary.
His 1807 successor to this secretarial post was Sir Humphry Davy, future mentor to Michael Faraday.
The younger daughter married in 1808 Taylor Combe, who subsequently assumed the junior secretarial role for the Royal Society.