On the advice of the anatomist Félix Vicq-d'Azyr (1748–1794) he took up medical studies, and after many difficulties caused by lack of means he finally obtained his doctor's diploma in 1780.

[1] The Royal Society's Catalogue of Scientific Papers enumerates fifty-nine memoirs by Fourcroy alone, and fifty-eight written with others, mostly Louis Nicolas Vauquelin.

By using newer methods than the alchemical tradition that had proceeded him, such as extraction and qualitative analysis, Fourcroy concluded that the brain was composed of fatty acids in combination with bases along with recording some physical properties of the substance.

[7] Fourcroy collaborated with physician Francois Chaussier to create a report that would be the basis of the Law of 1794, which integrated medicine and surgery and established health schools that taught both of these fields to all students.

The law pushed by Fourcroy unified the French medical education system under centralized authority, and led to the issuing of national licensing years later.

[4] Along with proposing these hospitals, and the idea that they should be staffed by young physicians well versed in modern sciences, Fourcroy wanted to include material obtained in post-mortem examinations in analysis of humans and how they are affected by disease.

By the end of that year, after holding several positions in the National Convention, he was elected as the president of the Jacobin party, taking a seat on the Committee of Public Safety in the process, which he held for about ten months.

As an important counselor to Bonaparte, Fourcroy was appointed Minister of Public Instruction in 1802, responsible for education in France at all levels, which he held until his death in December 1809.

However, it was Fourcroy that began to better describe the term by lengthening the time scale and broadening the map of nations that were contributing to the Chemical revolution in his written works.

[10] It was Fourcroy who had initially noted the division that chemistry had undergone from natural history, concluding that the two studies no longer shared objectives nor methods.

In episode one of The Mystery of Matter: Search for the Elements, "Out of Thin Air," Fourcroy's character is played by Yan Tual as he assists Lavoisier in his discovery of oxygen.