He was a pupil of Santo Prunato and Antonio Balestra and active mostly in the area of the Veneto.
He became the director of the academy of painting and sculpture of Verona in December 1764.
Among his many pupils were Maria Suppioti Ceroni,[1] Giovanni Battista Lorenzi, Saverio Dalla Rosa, Domenico Mondini, Domenico Pedarzoli, and Christopher Unterberger.
For the Austrian governor of Lombardy and a collector of antiquities, Count Karl von Firmian, Cignaroli painted two canvases on Greco-Roman episodes, a thematic preferred by Neoclassic painters: Death of Cato (1759) and Death of Socrates.
Giambettino was born into a family of artists, and this tradition continued after his death with his children.