After passing his A-levels he read philosophy, history, Greek literature, and Sanskrit at the universities of Bonn and Berlin.
In 1838 Delius finished his studies with a promotion in Bonn (doctoral thesis: Radices pracriticae) and taught at Berlin University afterwards.
About a year later he made up his mind to work as a private lecturer at Bonn University.
Delius was a co-founder and for years to come chairman of the Deutschen Shakespeare-Gesellschaft (German Shakespeare Society).
He left his valuable Shakespeare collection to the Bremen public library.