Brescia Tonali made his professional debut for
Brescia Calcio on 26 August 2017, aged 17, coming on as a substitute in the
Serie B away match lost 2–1 against
Avellino. On 28 April 2018 he scored his first professional career goal, in a 4–2 defeat against
Salernitana in Serie B. He obtained 19 league appearances in total during his first season as a professional player, scoring two goals and providing two assists during the
2017–18 Serie B season. The following season, Tonali won the
Serie B title with Brescia, and achieved promotion to Serie A, featuring as a starter for the club throughout the entire 2018–19 season. He made his Serie A debut on 25 August 2019, aged 19, in a 1–0 away win against
Cagliari. On 29 September, he assisted
Mario Balotelli's goal from a corner kick in a 2–1 away loss to
Napoli; he also scored a goal during the match with a powerful shot from outside the area, which was disallowed by
VAR, however, for a foul by Brescia's
Dimitri Bisoli on Napoli's
Nikola Maksimović. He scored his first Serie A goal on 26 October, netting a long-range
free kick into the top corner from the left flank, which was the opening goal in an eventual 3–1 away defeat to
Genoa.
AC Milan 2020–2021: loan On 9 September 2020, Tonali joined
AC Milan, on a season-long loan for €10 million with an option to buy for €15 million, plus bonuses worth €10 million. The player will earn a yearly wage of €2 million for five years. Tonali made his competitive debut for Milan on 17 September 2020, coming on as a substitute in the 83rd minute in a 2–0 victory against
Shamrock Rovers FC in the second round of Europa League qualifying. He made his Serie A debut for Milan on 21 September 2020, coming off the bench in the 77th minute in a 2–0 victory over
Bologna FC 1909 at the
San Siro. Tonali finished the season with 37 appearances, 23 of those in the starting eleven.
2021–2022: Serie A champion in 2022 On 8 July 2021, Milan officially purchased Tonali's rights from Brescia and he signed a five-year contract with the club. He took a pay-cut to secure his childhood dream move to Milan and was praised by the fans on social media for this gesture. Tonali scored his first goal with Milan's shirt on 29 August 2021 against Cagliari, a free kick that opened the scoresheet in eventual 4–1 win. On 3 October at
Gewiss Stadium against Atalanta, Tonali dispossessed the ball from
Remo Freuler and ran to the opponents box to score the second goal in eventual 3–2 victory for Milan. On 25 February 2022, Tonali
assisted Rafael Leão's goal against Udinese, becoming the youngest midfielder to have scored more than one goal (two) and delivered more than one assist (two) in Serie A that season. On 24 April as the match against
Lazio was heading to 1–1 draw, Tonali scored the winner in the stoppage time, securing the lead for his team in Serie A table. On 8 May 2022, his 22nd birthday, Tonali scored an equalising and a winning goal in the 3–1 away Serie A victory against
Hellas Verona. The comeback victory brought Milan back on top of the Serie A following Inter's 48-hour stay there in a close championship race. Tonali is also the youngest midfielder to have scored five or more goals in Serie A that season (and the second-youngest among all players, older only than Bologna's
Aaron Hickey). After 3–0 away win against
Sassuolo on 22 May, Milan secured their first Scudetto in 11 years, In total, Tonali played 36 games in the campaign, scoring 5 goals and providing 3 assists. Tonali's performance that season brought the attention and praise of renowned Italian football pundits, the likes of
Paolo Di Canio,
Roberto Donadoni and
Fabio Capello, the latter went on to state that Tonali would have found a place in even the greatest of Milan's generation in the past.
Newcastle United On 3 July 2023,
Premier League club
Newcastle United announced the signing of Tonali on a five-year contract, for an undisclosed fee. Reported to be around €70 million, this made Tonali the most expensive Italian player of all time. On 18 July, he made his debut for Newcastle in
Allan McGregor's testimonial match against
Rangers. On 12 August, he scored the opening goal on his Premier League debut in a 5–1 win over
Aston Villa. On 18 October 2023, Newcastle announced Tonali was being investigated by the Italian Prosecutor's Office and the
Italian Football Federation for alleged illegal betting activity. On 26 October, he was banned from playing football for 10 months for breaching Italian betting regulations. This included eight months in gambling rehabilitation. This meant he would miss the rest of the
2023–24 season and
UEFA Euro 2024. In March 2024, he was charged with misconduct in relation to alleged breaches of the
Football Association's betting rules. The FA alleged that Tonali broke rules by placing bets on matches between 12 August and 12 October 2023. He was handed an additional two-month suspended ban by the FA for these breaches in May 2024, though he was allowed to return to football in August on the condition that no further breaches were made during the 2024–25 season. On 28 August 2024, after serving his suspension, Tonali made his first appearance since October the previous year, playing 61 minutes of a 1–1 draw against
Nottingham Forest in the third round of the
EFL Cup. Four days later, he made his Premier League return, appearing as a 68th minute substitute for
Sean Longstaff in a 2–1 win over
Tottenham Hotspur. On 16 March 2025, Tonali became part of the first Newcastle United side to win a major domestic trophy in 70 years when he played the full 90 minutes in the
2025 EFL Cup final. Tonali had scored two goals in the quarter-final against
Brentford to help the club reach the final. In October 2025, it was reported that Tonali had signed a contract extension with Newcastle United during his betting ban, extending his deal until 2029 with an option for a further year to 2030. == International career ==