In 1985 Milletich joined the Compress Group, a publishing house of which he became managing director in 1990. When the Compress Group was sold to Bohmann Publishing in 1999, he became its co-managing director. In 2004, together with his co-managing director Gabriele Ambros, he bought the publishing house from its previous owner, the Dutch group
Wolters Kluwer, and has since held a 50 percent stake in it. In 2011, under his leadership, Bohmann-Verlag took over
Burgenländische Kabelfernsehen (BKF) and converted it into the regional broadcaster for the eastern region Schau TV, but sold it to
KURIER Medienhaus in 2017 due to economic problems. In May 2020, it was announced that Milletich would move part of Bohmann-Verlag to his home municipality of Parndorf, and the topping-out ceremony for the media house in
Parndorf was held in September of the same year. In 2013, Milletich was granted the right to use the professional title Kommerzialrat due to his economic merits. Gerhard Milletich is a member of the
Burgenland Croatian ethnic group. ==Involvement as a soccer official==