The following match against Empoli, Bonaventura came on the pitch as the substitute for Suso in the 55th minute and managed to assist Luiz Adriano's winning goal from a corner kick 15 minutes later.
On 19 September, Bonaventura assisted Carlos Bacca's first goal and scored directly from a free-kick in a 3–2 win over Palermo.
He also gained another assist and goal in Milan's next game, the 2–3 win over Udinese.
Once again, he assisted both Carlos Bacca's and Philippe Mexès' goals against Lazio in the 3–1 away win on 1 November.
He continued to perform well under the team's coach Siniša Mihajlović and became a fundamental player for his team throughout the season.
After missing a 0–0 draw against his former team Atalanta through suspension, he scored the opener in a 4–1 defeat of Sampdoria on 28 November.
He scored again in his next game on 1 December, a 3–1 Coppa Italia defeat of Crotone, via a brilliant 20-yard free kick.
On 20 December he assisted Carlos Bacca's goal and scored a late goal as Milan beat Frosinone 4–2.
1989
Giacomo “Jack” Bonaventura (born 22 August 1989) is an Italian professional footballer who plays as a midfielder for Serie A club Fiorentina and the Italy national football team.
2007
Bonaventura started his senior career at Atalanta in the Serie A in 2007, his impressive performances earning him a €7 million transfer to AC Milan in 2014, spending six seasons at the club, before leaving in 2020.
He only played this match in the whole 2007–08 season.
He appeared again on 9 November, against Fiorentina.
2008
Bonaventura has been a youth national team member since 2008.
Bonaventura made his debut with Atalanta on 4 May 2008, in a match against Livorno.
2009
On 13 January 2009, Atalanta announced he had joined Pergocrema on loan for the remainder of the 2008–09 season.
Five days later, he made his debut for Pergocrema, getting on the scoresheet in a match against Sambenedettese.
He made three more appearances before returning to Atalanta.
2010
He returned to La Dea, but had to wait until January 2010 to appear again, this time against Palermo.
On 1 February, he joined Serie B club Padova on loan until the end of the season.
He made his debut for the club on the 20th, against Triestina.
In June 2010, Padova decided not to buy him outright, and Bonaventura returned to Atalanta, signing a contract extension until 2015.
On 9 November, he scored his first Atalanta goal, against Modena.
2012
He played a key part for La Dea during the 2010–11 season, scoring nine times, with his club being crowned Serie B champions, thus earning promotion to Serie A. On 11 April 2012, he scored his first Serie A goal, against Napoli, before scoring again in a 2–0 victory against Fiorentina on 29 April.
2013
He made his senior international debut on 31 May 2013, in a friendly match against San Marino.
After playing for San Francesco 93' youth team, he was transferred to Tolentino, where he was noticed by one of Atalanta's scouts, Antonio Bongiorni.
He scored his first brace on 3 March 2013, in a 2–0 victory against Siena.
2014
In late August, Atalanta and Hellas Verona had agreed for the signature of Bonaventura and Verona's ex sporting director, Sogliano, had talked to Giacomo but on 1 September 2014, in the last hours of the Italian transfer window, AC Milan announced the signature of Bonaventura from Atalanta for a fee reported to be around €7 million after they failed to sign Jonathan Biabiany.
His agent later revealed that Bonaventura cried after signing for Milan as his dream became true.
He was given the number 28, which was previously worn by Urby Emanuelson.
On 14 September, Bonaventura scored a goal on his debut as Milan beat Parma 5–4.
Bonaventura scored his second goal for Milan on 29 October against Cagliari and was voted man of the match.
On 12 December, Bonaventura scored a powerful header and assisted Jérémy Ménez's goal as Milan defeated Napoli 2–0; Bonaventura was also voted man of the match against Napoli and again in the next week against Roma.
The following match against Sassuolo, he scored a goal and later in the match he received a second yellow card and was sent off.
It was the first time in his career that he was sent off.
On 30 May, he scored twice against his former team Atalanta in a 3–1 victory.
Bonaventura finished his first season at Milan with 7 goals and 4 assists in all competitions.
2015
On 23 August 2015, Bonaventura made his season debut as Milan lost 2–0 to Fiorentina.
2016
On 17 January 2016, he provided another assist for Carlos Bacca as the Rossoneri beat Fiorentina 2–0.
He ended the season with 7 goals and 8 assists in all competitions as Milan finished 7th in Serie A, and lost out in the Coppa Italia final against Juventus, following a 1–0 defeat in extra time.
At the beginning of the season, Bonaventura switched his number from 28 to 5.
