After a year of further studies in Göttingen and Rome he began teaching Latin at gymnasiums, from 1912 to 1919 in Arnhem and from 1919 to 1924 in The Hague.

In 1924 he became professor of Latin language and literature at the University of Groningen and during the following years he directed his efforts at examining religion in the late Roman Republic and the early Imperial Rome.

He moved to Utrecht in 1930 to succeed Pieter Helbert Damsté (who directed Wagenvoort's doctoral dissertation) as professor of Latin.

His inaugural lecture was called Pax Augusta, in line with his earlier research, but gradually his interest shifted to the religion of the earliest Rome and "primitive survivals" in later Roman religious life.

He published a great number of articles but also directed 38 doctoral dissertations (2 in Groningen and 36 in Utrecht), an unusually high amount in the field of classical studies.