His son Gaetano Giorgio Gemmellaro was a noted geologist, paleontologist and politician, who served as rector of the University of Palermo.

Carlo was born to a prominent family; his uncle had performed observations on the eruptions of Mount Etna.

Carlo studied medicine at the University of Catania, and began practicing as a physician in Messina.

[2] The events of 1837, when an epidemic of cholera afflicted Catania, fomented rebellion in the town, Carlo went on to publicly criticize the response of the autocratic Bourbon monarchy.

As volcanologist, he studied Etna in Sicily; his studies are summarized in the monograph Vulcanologia dell'Etna 1859-1860 which is certainly the most mature product of the Gemmellaro research, synthesis of observations carried for decades and successful attempt of a modern volcanic theory.