Messerli studied architecture at the ETH Zurich. After leading restoration work in the old city of Sanaa, Yemen, in 1993, he worked as an architect in Basel. In 1995 he attended the theater school "Ecole Philippe Gaulier" in London and worked in the independent theater scene as an actor and stage designer. Since the 1999/2000 season he has been working regularly as a stage designer at the Stadttheater Bern/ Konzert Theater Bern. Today Jann Messerli works as a freelance stage designer and architect.