From 19-24 years old, de Maquillé was the president of LGO in France, responsible for organising four music festivals per year and managing a rehearsal studio. After graduating with a Masters of Electronic Engineering, he moved to Southeast Asia and co-founded a group of building technology companies called iHome Systems, establishing branches in Thailand, Vietnam, Malaysia, and Singapore, before selling the group to a large multinational company. Guillaume founded gigBazaar, the first online community marketplace for the music industry in South East Asia, before chasing his dream of operating music festivals in the region, full-time. He has been involved in a myriad of projects including Wonderfruit, Karma Klique, LUSH, Paradise Island Festival, Quest Festival, Kolour in the Park, and many more.