He was heavily influenced by his eldest sister Pulcheria who pushed him towards orthodox Christianity. Pulcheria was the primary driving power behind the emperor and many of her views became official policy. These included her anti-Semitic view which resulted in the destruction of synagogues.
In 429 Theodosius appointed a commission to collect all of the laws since the reign of Constantine and creating a fully formalized system of law. This plan was left unfinished, but the work of a second commission that was assigned to collect all of the general legislations and bring them up to date was completed, and their collection published as the Codex Theodosianus in 438.
During this time he was responsible for the creation of the Constantinople University.
He died in 450 as the result of a riding accident.