[1] In 1739, he joined the Order of Saint Benedict, Camaldolese at the monastery of Sant'Apollinare in Classe near Ravenna.

[1] He later served as the theologian of Ferdinando Romoaldo Guiccioli, Archbishop of Ravenna, from 15 June 1753 until 1763.

[1] In this capacity, he served under Cardinal Giovanni Angelo Braschi, the monastery's commendatory abbot, who became Pope Pius VI in February 1775.

In the consistory of 23 June 1777, Pope Pius VI made Gioannetti a cardinal in pectore.

[1] In March 1799, Austrian and Russian troops occupied Bologna, enabling Gioannetti to reestablish his authority.