In 1887 he obtained an appointment at the National Museum of Antiquities at Saint-Germain-en-Laye; in 1893 he became assistant keeper, and in 1902 keeper of the national museums. In 1903 he became joint editor of the Revue archéologique, and in the same year officer of the Legion of Honour. The lectures he delivered on art at the École du Louvre in 1902-3 were published by him under the title of Apollo. These were translated into most European languages, and became a standard handbook on the subject.
Reinach's first published work was a translation of Arthur Schopenhauer's Essay on Free Will (1877), which passed through many editions. This was followed by many works and articles in the learned reviews of which a list—up to 1903—is available in Bibliographie de S. R. (Angers, 1903). It has been said his bibliography runs to 262 pages and includes more than ninety lengthy works and at least seven thousand articles. (Curtis, 2003)  His Manuel de philologie classique (1880-1884) was crowned by the French association for the study of Greek; his Grammaire latine (1886) received a prize from the Society of Secondary Education; La Nécropole de Myrina (1887), written with E Pottier, and Antiquités nationales were crowned by the Academy of Inscriptions. He compiled an important Répertoire de la statuaire grecque et romaine (3 vols., 1897–98); also Répertoire de peintures du Moyen âge et de la Renaissance 1280-1580 (1905, etc.); Répertoire des vases peints grecs et étrusques (1900). In 1905 he began his Cultes, mythes et religions; and in 1909 he published a general sketch of the history of religions under the title of Orpheus. He also translated from the English HC Lea's History of the Inquisition.