Giovanni Vianello was born in Venice in the "sestiere di Castello" in 1730 from Antonio, son of Zne Mariner (Giovanni seaman), and Elena Nordio. According to his baptism act, his name is Giovanni Iseppo (Venetian variant of Giuseppe). After 28 years of marine trading and five years in a merchant house in Cairo, Egypt, he moves to Salonica around 1766 as a partner in a merchant firm "Rotta, Vianello et Cie". His partner Giuseppe Rotta and himself are consultants at the Salonica tribunal.
Giovanni will be appointed in various occasions as vicar of the Venetian consul (the consul in charge being M de Choch), and subsequently vice-consul of Austria (from 1803 to 1805) at the same time as vice-consul of Russia in 1803.
In 1805 the trading firm becomes "G. Vianello & Sons". It is reputed among the richest merchant firm of Salonica.
After the Treaty of Pressburg (26 December 1805) that separates Venice and its region from the Austrian Empire to attach it to the napoleonic Italian Kingdom, the Vianello familly chooses the Austrian citizenship.
In 1788, Giovanni Vianello marries Clara Pradel, daughter of Giorgio and Anna Daperi. The marriage is celebrated in the residence of Luigi Biskuitter, father-in-law of the bride.
They will give birth to six children:
- Elena who will marry Giuseppe Wessely,
- Niccolò who will marry Emilia Charnaud,
- Antonio,
- Giorgio who will marry Charlotte Adèle Lafont,
- Giovanni,
- Anna who will marry Giovanni Wessely (nephew of Giuseppe)
Giovanni dies in Salonica in 1818