George Gallier began his career in the film industry in Paris, working at Les Films du Losange with Margaret Menegoz, where he assisted director Barbet Schroeder on More and The Valley, and collaborated with Éric Rohmer on Perceval le Gallois. He later transitioned into fashion photography and model management, becoming an early innovator in modern personal management for models, actors, and celebrities. As head of Prestige Model Management in Paris, he discovered and developed leading talent including Laurence Treil, Estelle Lefébure, Estella Warren, Vanessa Duve, Connie Nielsen, and Adwoa Aboah. He also co-owned Jill, a prominent French fashion magazine that played a key role in launching several of these careers and regularly featured work by photographers such as Peter Lindbergh, Patrick Demarchelier, Hans Feurer, and Peter Beard, with fashion direction by Babette Djian. Gallier later relocated to New York to found American Model Management, introducing a holistic, career-focused management model that helped set new industry standards in the United States. In 2012, he co-founded The Lions Models LLC in New York City with Ron Burkle of The Yucaipa Companies.