[4] He began his studies in 1720 at Lund University,[5] where he became assistant professor of law in 1731, then spent a few years in Stockholm as a teacher for the von Fersen family, during which time he had the opportunity to conduct research in the National Archives.

[6][3] In 1751 Lagerbring became juris doctor, in 1755 a member of Queen Louisa Ulrika's Academy of Letters, History and Antiquities,[7] and in 1770 permanently on leave from his professorship for scientific work.

In the disputation series Monumenta scanensia (36 dissertations in two volumes, 1744–1751), mainly a publication of medieval sources on the history of Scania, extracts from King Valdemar II's Danish book of land taxation, Liber daticus ecclesiæ lundensis and Necrologium lundense were printed for the first time.

A similar source publication was also Lagerbring's Samlingar af åtskilliga handlingar och påminnelser, som förmodligen kunna gifva lius i swänska historien (three volumes, 1749–1758).

As evidence of his critical ability, he raised doubts about the authenticity of the papal bull of Pope Agapetus II, and was also on the trail of the Hamburg-Bremen Church's document forgeries.

Lagerbring had several points of contact with contemporary scholars such as Jakob Langebek, Peter Frederik Suhm, Gerhard Schøning, and Terkel Klevenfeldt [da].

[3] Due to his style being less nationalistic and having less of a causerie tone, Lagerbring's work did not receive the appreciation it deserved at the time and in the near future.

Lagerbring has certainly not been surpassed by any previous Swedish historian in critically astute scholarship; in many places he has set out guidelines which the scholarly work of a later period has followed.

[3][4][12] A bust of Lagerbring, made by the artist Albert von Stockenström [sv], has stood on the University Square in Lund since 1907.

[14][15] At the beginning of his career, Lagerbring proposed a pseudoscientific theory that Swedes were of Turkish origin, based on superficial similarities between the two languages and the fact that sources such as Ynglinga saga and Prose Edda states that Odin migrated to Sweden from a land called Tyrkland.