Grillo was born in Savignone, a small town in the Province of Genoa, Liguria.

After receiving his degree as an accountant, Grillo became a comedian by chance, improvising a monologue in an audition. Two weeks later he was discovered and launched by Italian TV presenter Pippo Baudo. In the 1980s his success rose further, thanks to shows like Te la do io l'America and Te lo do io il Brasile.

As a result, his popularity grew more and more, and he became the protagonist of another show developed especially for him, called Grillometro (Grillometer).

Soon after this, his performances began to be characterized by an increasing level of political satire, often expressed in such a direct way that he quickly offended a lot of Italian politicians. I

Consequently, from the beginning of the 1990s his appearances on television became rare: according to many people, the reason for this is a silent ostracism by politicians offended by his revelations about their hidden financial activities, frauds and false claims. When one of his shows was finally allowed to be broadcast by RAI, in 1993, it obtained a record share of 16 million viewers.Then, he have been censored from italian television definitively because of fhis innovative ideas that provoked a clash between him and politicians.