After early training with his grandfather, he studied violin at his hometown's conservatory of music, in Trieste, then in Venice, and later at the Accademia Chigiana in Siena.
Agostini has appeared in various international music festivals in Europe, United States and Japan and has performed chamber music with many distinguished artists including Bruno Giuranna, Jaime Laredo, Joseph Silverstein, Janos Starker as well as with members of the American, Emerson, Fine Arts, Tokyo and Guarneri quartets.
Among Agostin's Philips recordings there are Bach and Vivaldi's violin concertos, including the Four Seasons, which was filmed on location in Venice and available also on DVD.
Other recordings include the Fauré's 'Piano Quartets' produced by Claves and, more recently, an Hommage à Nathan Milstein, a selection of favorite virtuoso violin pieces, published by 'Live Notes' in Japan.
He has taught eight years in the Conservatories of Venice and Trieste, Italy, and ten years at the Staatliche Hochschule für Musik in Trossingen, Germany; has given numerous master classes at music universities in the United States, Canada and Mexico, as well as in Italy, Germany, Denmark, Sweden, Japan and Australia.