During the season 2006–2007, Bolzoni was part of the winning side, when the reserve won the Campionato Nazionale Primavera (under-20 Italian Championship).
He made his first-team debut on 1 February 2007, playing 26 minutes of 2006–07 Coppa Italia) semi-final return leg against Sampdoria at the Stadio Giuseppe Meazza.
[3][4][5] In July 2010, Siena signed Bolzoni on loan for €400,000[6] with an option to acquire 50% of his economic rights,[7] fact that occurred on 22 June 2011,[8] for €1,050,000.
[21] Upon his return from loan, Bolzoni did not make any appearances for Bari in the first half of the 2021–22 season, and on 26 January 2022 his contract with the club was terminated by mutual consent.
[23] On 5 October 2007, Pierluigi Casiraghi called up Bolzoni, although still 18 years old, to form part of the Italy U-21 national team for the matches against Croatia and Greece.
[24] On 21 November 2007, he made his debut for the Italy U-21 national team, in a qualification match against Faroe Islands but did not make the final 23-man squad for the tournament.