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 Vlaamse Opera (now Opera Vlaanderen), he directed at more than 30 opera houses in Europe. In 2005 he made his debut in New York with Gounod's 'Romeo & Juliet'.
Joosten founded the Opera Studio Flanders in Ghent, a postgraduate course for opera singers, and teaches at the Institut del Teatre in Barcelona (ES). Since October 2013 he has been the artistic director to the Opera Studio, renamed International Opera Academy. In addition to this, Joosten teaches presentation, acting, and opera and scenic improvisation at the Conservatory in Antwerp.