Giancarlo Fassina worked as an exhibition designer, concentrating on the light planning of showrooms. In 1983 he designed the complete lighting concept for the "Hayez" exhibition in the Palazzo Reale in Milan and for the exhibition "Design U.S.A." in the Sforzesco Kastell in Milan. Furthermore together with the architect Marco Zanuso Fassina developped the light planning of the new theatre Fossati in Milan.
In cooperation with the designer and architect Michele de Lucchi he designed the timeless lighting series "Tolomeo" (1987), for which the two designers were awarded the "Compasso d’Oro" prize.
Giancarlo Fassina cooperated with the most important companies in the lighting sector, such as Artemide and Luceplan, for which he created together with Carlo Forcolini the "Birzi" table lamp.