In 1999, Gillern received a Master of Arts with honors in Theology and Christian Ministry from Franciscan University of Steubenville.

In 2003 he was appointed by United Nations Industrial Development Organization (UNIDO) in Vienna (Austria) as a research assistant.

In September 2007, he flew home to his mother, Kathryn Gilleran, in Cortland, New York, to visit his family for ten days.

[5] The Austrian police changed their statement multiple times, as well as denying the presence of any witnesses, despite a phone call they had received from a couple only a day after Gillern was declared missing.

[3] Each year since 2008, Gillern's mother has held a vigil every October 29 outside the Kaiserbründl to commemorate the disappearance of her son.