From 2019-2020, Artistic Executive Director of the Onassis Foundation USA, an innovative programming foundation based in Athens with satellites in New York and Los Angeles. Artistic Director of Performance Space 122 (now Performance Space New York) from 2005-2017 and a consulting curator for BAM and Theater de Welt. For 20 years, working across live performance in all disciplines, cinema, design and hospitality Gantner has sought innovative artists, work, and ideas building new experience and forms of communication for audiences.

He is the chair of Hoovie – a new model of film distribution developing innovative ways that enable independent film screenings in private spaces, and MKRS, a company supporting creative urban ecosystems of artists, artisans and ideas people. A board member of Myer Family Investments, and Jianguo, both diversified investment companies based in Melbourne. He is currently engaged in driving these toward a new strategy of sustainable investment.

He also serves on the boards of the Chocolate Factory (NYC), VII Photos and various philanthropic institutions in Australia.