[5] Son of a Tuscan worker (his father Amerigo, a former professional cyclist, worked as a crane operator at Italsider in Bagnoli, a district of Naples),[6][7] Sarri was raised in Castro (province of Bergamo) and then in Faella (municipality of Castelfranco Piandiscò, in the province of Arezzo), where he divided his time as an amateur footballer and banker for Banca Monte dei Paschi di Siena in Tuscany.

[12] At the age of 19, Montevarchi was close to signing Sarri but Figline asked for a compensation of 50 million lire, and the deal eventually collapsed.

[18] After avoiding relegation, he left the club on 30 June 2006 and was appointed at the helm of fellow second division side Arezzo on 1 November, in the place of the sacked Antonio Conte.

[21] On 31 December, he replaced fired Davide Pellegrini at the helm of Hellas Verona,[22] but was himself sacked the following 28 February after winning only one point during his six matches in charge.

Sacked on 15 February of the following year, he was replaced by the outspoken manager Robert Cerullo, CPA, MBA and he only returned to coaching duties on 24 March 2010 with Grosseto.

On 6 July of that year, Sarri was appointed manager of Alessandria in Lega Pro Prima Divisione,[24] and reached the promotion play-offs, being knocked out in the semifinals by Salernitana.

[35] This worked to great effect, as the Belgian netted 28 goals as the club finished third in 2017, while Sarri was voted the league's coach of the year, and received the Enzo Bearzot Award.

Sarri, whose Napoli side had concluded the first half of the 2015–16 season Serie A in first place, gained the title "Campioni d'Inverno" ("Winter Champions") for the first time in 26 years.

[42] Sarri became the first head coach or manager to remain undefeated throughout his first 12 Premier League fixtures,[43] until 24 November, where they lost 3–1 to Tottenham Hotspur.

An irate Sarri nearly stormed into the stadium tunnel, and was later held back by Chelsea defender Antonio Rüdiger from confronting the keeper.

[48] On 29 May, Sarri won his first major trophy as a manager after Chelsea beat Arsenal 4–1 in the 2019 UEFA Europa League Final in Baku.

[50] At the end of the 2018–19 season, Chelsea announced that Sarri was departing to become manager of Juventus, with the club statement also mentioning his desire to be closer to his elderly parents in Italy.

[54] Under Sarri's management, Juventus participated in the 2019 Supercoppa Italiana on 22 December, following their league title victory in the previous season, where they lost 1–3 against Lazio at the King Saud University Stadium in Riyadh.

[55] On 17 June 2020, Juventus suffered a 4–2 penalty shoot defeat to Sarri's former club Napoli in the Coppa Italia Final, following a 0–0 draw after regulation time.

[62] From a tactical standpoint, Sarri is known for his intelligence, attention to detail and his meticulous approach in preparing for matches during weekly training sessions.

Other key elements of Sarri's line-up are the presence of a deep-lying playmaker who dictates play in front of the back-line, such as Jorginho, and overlapping attacking full backs, to provide width to his team, as his players often attack from the flank, looking to play quick exchanges and make runs in behind into the box rather than deliver crosses into the area, however.

[65] During the 2016–17 season, following the departure of Gonzalo Higuaín to rivals Juventus and an injury to the club's main striker Arkadiusz Milik, Sarri frequently used Dries Mertens in a false nine role, seemingly positioned as a lone centre-forward, rather than as a left winger, where he had previously faced competition from Lorenzo Insigne for a starting role.

[8][63][71] At Chelsea, he also adopted a more relaxed approach than his predecessor Antonio Conte when it came to his players' diets and curfew before matches,[76] which along with the changes in tactics to a more offensive-minded, possession game based on passing, helped create a more positive team environment; receiving praise from his Chelsea player Antonio Rüdiger for doing so.

[82] The Italian encyclopaedia Treccani instead coined the term "Sarrismo" to describe the offensive and spectacular style of football that Sarri's teams play.

[83] Sarri's teams' modern, innovative and creative playing style, as well as their mentality, ability to move up the pitch quickly on counter-attacks and score many goals, has won praise from several pundits, players and managers, including Pep Guardiola and Cesc Fàbregas;[66][81][82][84][85] in 2018, former manager Arrigo Sacchi praised the style employed by Sarri's Napoli side as "the most important thing seen in Italy in the last 20 years".

[87] Sarri is a heavy smoker and in 2018, Napoli's UEFA Europa League opponents, RB Leipzig, built a special smoking section in the locker-room area of their stadium, Red Bull Arena, specifically for him.

[94] Sarri was consequently fined €20,000 and banned for two Coppa Italia matches by Lega Serie A for "directing extremely insulting epithets at the coach of the opposing team".

[95] In March 2018, Sarri came under further criticism in the media when he was accused of making sexist comments when responding to female reporter Titti Improta of Canale 21, who had asked him in a post-match interview if he thought that Napoli's title challenge had been compromised; he subsequently apologised,[96] later also adding that he had been joking.