He was co-founder and chairman of Casaleggio Associati srl, an internet and publishing company that advises on network strategies.

He was editor of Beppe Grillo's blog, and together they founded the Five Star Movement, of which Casaleggio was sometimes called the "guru".

[3] Born in Milan, Casaleggio began his career working at Olivetti, then, in the late 1990s, became CEO at Webegg, an internet consulting company.

Webegg suffered heavy losses (over €20 million) in the period 2002–2003, and Casaleggio was replaced as CEO in 2003 by Giuseppe Longo.

[8] After Gianroberto's death, his son Davide was appointed to replace him as president of Casaleggio Associati.