He was the youngest of five children of Jacques Dominique, Comte de Cassini, famous for completing the map of France, who had succeeded his father as the director of the Paris Observatory. He was also the great-great-grandson of famous Italian-French astronomer, Giovanni Domenico Cassini, discoverer of Jupiter's Great Red Spot and the Cassini division in Saturn's rings.
He named many flowering plants and new genera in the sunflower family (Asteraceae), many of them from North America. He published 65 papers and 11 reviews in the [Nouveau] Bulletin des Sciences of the Société Philomatique de Paris between 1812 and 1821. In 1825, Cassini placed the North American taxa of Prenanthes (family Asteraceae, tribe Lactuceae) in a new genus Nabalus. In 1828 he named Dugaldia hoopesii for the Scottish naturalist Dugald Stewart (1753-1828).
Some genera (originally) named by him :
- Dracopis, coneflower
- Emilia, tasselflower
- Euthamia, flat-topped goldenrod
- Guizotia, niger-seed
- Heterotheca, camphorweed, golden-aster
- Pluchea, marsh-fleabane
- Cassini, Henri. 1813. Observations sur le style et le stigmate des synanthérées. Journal de Physique, de Chemie, d'Histoire Naturelle et des Arts 76: 97--128, 181--201, 249-75.
- King, Robert M., Paul C. Janaske, & David B. Lellinger (compilers). 1995. Cassini on Compositae II. Monographs in Systematic Botany from the Missouri Botanical Garden 54: [i]-xii, 1-190.