He was born in 1419 and was 67 years old, the younger brother of the previous Doge Marco.
Widower of Isabetta Soranzo , who had given him 5 children (4 girls and a boy), he was ambitious and boasted a good military and political career: he was among other things the mayor of Verona (1478) and Padua (1482), where his only son, Francesco, died; since then he grew the white beard with which he is portrayed at Villa Barbarigo in Valsanzibio (fraction of Galzignano Terme, near Padua).
He was captain general in the war of Ferrara or of the salt (1482-1484) and procurator of S. Marco de supra (25 November 1485).
He was described as a doge of great presence and eloquence,
Homo de dignna statura, de admiranda prexentia et non veduta la talle in our times , very wise, eloquent, of much memory and firm character. As doge he wanted the kiss of the hand and the genuflection of those who approached him. Before entering the Doge's Palace (March 19, 1492), restored after the fire of 1483, he demanded his heraldic coat of arms on all the jambs and fireplaces.
During his doge, major events took place. In 1489 he convinced Caterina Corner to cede the island of Cyprus to the Republic to compensate for the losses of Corone and Modone, defined as the eyes of the Republic for their strategic importance. In 1495 the success of the anti-French league at the battle of Fornovo led to the occupation, by way of pledge by the Republic, of the Apulian ports of Brindisi, Otranto, Gallipoli, Monopoli and Trani. In 1499 overturning the alliances he joined the king of France and with the treaty of Blois he managed to obtain Cremona and Ghiaradadda.
The election of Agostino Barbarigo exploded in MC the antagonism between the old houses (the longhi) and the new ones (the curti), to which Agostino belonged: his election was in fact the first derogation after the Flabanico reform of 1032, which prohibited the choice of a co-regent or the succession of two members of the same family. The members of the old houses protested vigorously also because they were unable to elect one of their own after Michele Morosini (1382).
Venetian historians and chroniclers have outlined his memory in dark colors: his tour in the well to distribute coins to the people had been fatal, in the crowd 5 children were crushed; after 10 years of reign, Priuli wrote, each one was annoyed ...
et moriva cum cativa fame, maxime de avaritia . He was accused of having tolerated and promoted favoritism and, after his death, he was accused of smuggling, corruption, non-payment of debts, as well as having practiced speculative activities even in the retail trade, taking advantage of his pre-eminent position.
He was buried with his brother who had preceded him. Then a new magistracy was immediately appointed, that of the Inquisitors on the Deceased Doge and a commission was set up to shed light on the complaints against him received by the Council of X: the investigation, made by the Correctors of the Ducal Promission and by the Inquisitors on the Deceased Doge , lasted two years (it closed on 16 September 1503). The results of the commission were secreted, but the Correctors of the Ducal Promise received the task of
metere tale freno al doxe ch’el no fazi onnipotente come misser Augustin Barbarigo and it was reiterated that the Doge and his family could not accept gifts. It was later discovered that the investigation did not ascertain plots against the Republic, but instead ascertained that the Doge had illegally entered into possession of sums, in the form of gifts, which the heirs had to return.