Gmelin was appointed professor of medicine in Tübingen in 1772, and in 1775 accepted the chair of medicine and chemistry at Göttingen. In 1788 he published the 13th edition of Linnaeus'Systema Naturae with many additions and alterations.
The third son, Philipp Friedrich (1721-1768), was extraordinary professor of medicine at Tubingen in 1750, and in 1755 became ordinary professor of botany and chemistry.
One of his nephews, Ferdinand Gottlob von Gmelin (1782-1848), became professor of medicine and natural history at Tubingen in 1805, and another, Christian Gottlob (1792-1860), who in 1828 was one of the first to devise a process for the artificial manufacture of ultramarine, was professor of chemistry and pharmacy in the same university.
In the youngest branch of the family, Philipp Friedrich had a son, JohannFriedrich (1748-1804), who was appointed professor of medicine in Tubingen in 1772, and in 1 775 accepted the chair of medicine and chemistry at Göttingen.