Giorgetti joined the Italian Social Movement in 1975 and served as the party's provincial secretary in Verona. In 1995 he joined National Alliance (AN).
Five times elected to the Regional Council of Veneto (1995, 2000, 2010, 2005 and 2015) for AN (1995, 2000 and 2005), The People of Freedom (2010) and finally Forza Italia (2015), he was regional minister for 20 consecutive years: minister of Environment in Galan I Government (1995–2000), minister of Public Works in Galan II Government (2000–2005), Galan I Government (2005–2010) and Zaia I Government (2010–2015). Since 2015 he has been Vice President of the Regional Council.
He is the elder brother of Alberto Giorgetti, who was regional leader of National Alliance, has been a long-time member of the Chamber of Deputies and served as under-secretary of Economy and Finances to minister Giulio Tremonti in Berlusconi IV Cabinet.