Guy Joosten started out as artistic director and producer at Blauwe Maandag Compagnie, a theatre collective he co-founded. He also directed plays for other companies in Flanders and the Netherlands. After that, he worked at the Burg Theater in Vienna (AT) and a year later as head director at Thalia Theater in Hamburg (DE). In 1991, Joosten made his change-over from theatre to opera. Following his debut at Opera Ballet Vlaanderen, he directed at more than 30 opera houses in Europe. In 2005 he made his debut in New York and in 2018 in Asia (Seoul and Tokyo). In 2015 he was awarded the famous Italian Premio Abbiati for 'best director'.

Joost teaches opera courses at the Royal Flemish Conservatoire in Antwerp and founded the International Opera Academy. He gives regular masterclasses, e.g. in Sofia and Tel Aviv.