Mège was born on 24 october 1817 in Draguignan (old city in the south of France) where his father was teacher in primary school. In 1850 he added the name of his mother Mouriès to that of his father.

After studies in a local secondary school, he was a pharmacy assistant in Draguignan and later in Aix-en-Provence. In 1838 he got a position in the central pharmacy of the Hôtel-Dieu hospital in Paris. Rapidly, Mège did several practical researches in different fields of industrial chemistry. After improving successfully a drug preparation, Copahine, used against syphilis, he obtained patents for effervescent tablets, paper paste (1845), sugar and leather fabrications (1848).

In 1852, he was interested in research in animal and human feeding in promoting the use of calcium phosphate. This application was heavily supported by Chevreul at the Académie des Sciences.

From 1854 to 1860, Mège worked on bread production. His new procedure was more complicated than the current one but it improved the yield of the final product by 14%. However, it seems that his procedure was practically adopted only by the French army. For this work, he received a gold medal and the Légion d'honneur from Napoléon III on 23 february 1861.

After having a son, Hippolyte René, with Elisabeth Bance in 1855, he married this woman in 1861. She died in 1865 and was burried in the Père Lachaise cimetery in Paris.

After 1862, Mège worked exclusively on fat processing. We do not know the origin of this fertile orientation which ended with the famous patent concerning margarine accepted on 20 october 1869 in Paris (N° 86480): "Demande d'un brevet d'invention de quinze ans pour la production de certains corps gras d'origine animale" . Mège won a prize  for the discovery of a new fat product after the French government promised a reward to anyone who might discover a process for manufacturing a satisfactory substitute for butter. In the Imperial farm of the Faisanderie in Vincennes, he observed that fasting cows produced milk and, thus, deduced that butter fat should be first formed in animal tissues. From this erroneous hypothesis, he processed beef tallow until he obtained a liquid fat, oleo-margarine (from the name margaric acid given by Chevreul in 1813 to a mixture of palmitic and stearic acids) which after mixing with skimmed milk gave a solid product first named "beurre économique" and later "margarine Mouriès" less expensive and more stable than butter. In 1871, Mège sold his invention to the Dutch firm Jurgens for 60,000 Francs. While his work on bread processing gave him a notoriety during his life, the invention of margarine will remain his most famous contribution for the future generations.

Mège obtained in 1875 a patent (N° 109792) for beef canning and lastly in 1880 a patent (N° 128721) for the use of sea water salt in human nutrition.

Mège died on 31 may 1880 from a liver disease and was burried in the Père Lachaise cimetery. It is said that only a newspaper from his birthplace honoured his death.