Wagner completed his curriculum in 1826 at Würzburg, where he mainly studied under Johann Lukas Schönlein in medicine and to Karl Friedrich Heusinger in comparative anatomy.

Aided by a public stipend, he spent a year or more studying in the Jardin des Plantes, under the friendly eye of Cuvier, and making zoological discoveries at Cagliari and other places on the Mediterranean.

He remained at the Hanoverian university until his death, being much occupied with administrative work as pro-rector for a number of years, and for nearly the whole of his residence troubled by ill health from tuberculosis.

Frequent journeys to the Mediterranean, the Adriatic, and the North Sea gave him abundant materials for research on invertebrate anatomy and physiology, which he communicated first to the Munich academy of sciences, and republished in his Beiträge zur vergleichenden Physiologie des Blutes (Leipzig, 1832–33, with additions in 1838).

In 1835, he communicated to the Munich academy of sciences his researches on the physiology of generation and development, including the famous discovery of the germinal vesicle of the human ovum.

As in zoology, his original researches in physiology were followed by a students' textbook, Lehrbuch der speciellen Physiologie (Leipzig, 1838), which soon reached a third edition, and was translated into French and English.

[2] In 1843, after his removal to Göttingen, he began his great Handwörterbuch der Physiologie mit Rücksicht auf physiologische Pathologie123.13.24, and brought out the fifth (supplementary) volume in 1852.

He occupied himself with the cabinet of skulls in the Göttingen museum collected by Blumenbach and with the excavation of prehistoric remains, corresponded actively with the anthropological societies of Paris and London, and organized, in co-operation with the veteran Karl Ernst von Baer, a successful congress of anthropologists at Göttinger in 1861.