Bertolacci began his career at Roma, and was signed by Milan in 2015. He has represented the Italy national team and Italy U21 national team, and also played for the Italy U17 national team and Italy U19 national team. He made his senior international debut in November 2014, in a friendly match against Albania.
Bertolacci started his career with the Roma academy. In January 2010 he was sent on loan to Serie A team, Lecce. He scored the first goal for Lecce against Juventus a game in which he scored a brace. In summer 2010, Lecce extended the loan and borrowed Simone Sini also from Roma.
On 22 June 2011, Lecce excised the option to purchase 50% of his registration rights for a pre-agreed fee of €500,000. However, Roma excised the rights against the option for €500,000. Thus, Lecce received €500,000 in net as an incentive for the loan. Then Bertolacci was loaned for another season to Lecce, in order to play as a regular and gain more experience.
Bertolacci scored against his parent club in a 2–1 defeat on 20 November 2011. On 30 June 2012, Bertolacci returned to Roma. In summer 2012 he was involved in the deal to sign Genoa's Panagiotis Tachtsidis. 50% of Bertolacci's player rights were tagged for €1 million and also 50% of Tachtsidis's rights for €2.5 million.
On 20 June 2014, Roma and Genoa renewed their co-ownership contract agreement with Bertolacci.
2014-2015 season with Genoa is Bertolacci's best season of his career. He scored 6 goals in 34 matches of Serie A, producing 8 assists and helping his team reaching the 6th place in the league.
In June 2015, Roma bought the other part of Bertolacci's player rights from Genoa for a sum of €8.5m. Subsequently, on 29 June 2015, Bertolacci joined fellow Serie A club A.C. Milan for €20m.
He scored his first Serie A goal for Milan in a 3–1 away win over Lazio on 1 November 2015.
Bertolacci started his international experience in Val-de-Marne under-16 international tournament. He played all 3 matches of the 2008 UEFA European Under-17 Football Championship elite qualification, in which Italy did not qualify to the next round. He was then promoted to the U19 team in January 2009 (as a consequence of the early exit of U-19 born 1990 team), played twice in 2010 UEFA European Under-19 Football Championship elite qualification and once in the elite round. He was also selected for the final stage, playing twice as starter. During the 2010–11 season he was capped twice for the U20 team in the Four Nations Tournament.
In April 2011 he received his first under-21 call-up. However, he was injured and missed the friendly. On 10 August 2011 he made his debut with the Italy U21 team, in a friendly match against Switzerland.
On 11 June 2013, Bertolacci scored a 94th-minute equaliser – his first goal for the under-21s – against Norway in the European U-21 Championships to ensure Italy topped their group. Italy went on to reach the final, though Bertolacci did not feature.
On 9 November 2014, he was called up by Antonio Conte to the senior squad ahead of a UEFA Euro 2016 qualifying match against Croatia and a friendly against Albania. On 18 November, he made his debut with senior team against Albania, playing for 70 minutes in a 1–0 win at Stadio Luigi Ferraris. On 28 March 2015, Bertolacci made his second appearance for Italy in a Euro 2016 qualifying match against Bulgaria in Sofia which finished 2–2.
Bertolacci is a quick, hardworking, versatile and well-rounded midfielder, who is also capable of playing in several other positions, due to his ability to aid his team both offensively and defensively. A left-footed player, he is usually delpoyed as a creative attacking midfielder, due to his vision, passing, technique, and striking ability, as well as his adeptness at making attacking runs.
Bertolacci married actress Nicole Murgia on 23 December 2015 and is brother-in-law with her brother, Alessandro, who is also a footballer.As of 15 July 2017.
As of 13 October 2015 Milan
Supercoppa Italiana: 2016