Their meeting began at 6.30 PM and lasted for an hour during which Jung is believed to have discussed with Jain the "personal reasons" that led to his resignation on December 22.
Delhi Chief Minister Arvind Kejriwal, his deputy Manish Sisodia and Labour Minister Gopal Rai, have already met Jung after he stepped down from the top post.
Jung and Jain have been at loggerheads over a range of issues, including outbreak of chikungunya and foreign visits by AAP ministers, during the former's tenure as Delhi's Lt Governor.
A day after his resignation, Jung's office had said "he would be returning to academics" but did not cite any reason for his sudden decision to exit administration.
Jung has had a bitter-sweet relationship with Delhi's AAP government over matters of jurisdiction. But his decision to quit was said to have no connection to that relationship.
Jung had also met Prime Minister Narendra Modi a day after resigning.