[7][8] Blanc played professional football for numerous clubs, including Montpellier, Napoli, Barcelona, Marseille, Inter Milan and Manchester United, often operating in the sweeper position.

After leaving Bordeaux in 2010 he became the manager of the France national team until 2012, replacing Raymond Domenech in the wake of the 2010 FIFA World Cup[9] and leading the country to the quarter-finals of UEFA Euro 2012.

Only a few years later did he settle as a defender following the advice from Michel Mézy, a position in which his physical stature (1.92 m, 86 kg) and his temperament would prove invaluable.

Despite a decent season, during which he managed to score six goals, he felt like he could not fully express his potential and returned to France after just one year, to Nîmes and then Saint Étienne, where again he imposed himself as one of the best defenders in the league.

Although Blanc scored 13 goals in his last season at Saint-Étienne, les Verts were almost relegated, only staying up because Marseille were not allowed to return to the first division because of the club's financial difficulties.

Blanc quickly became a leader in a team that was desperately lacking confidence, and helped Marseille finish in fourth place in his first season, during which he scored 11 goals and earned the nickname "Le Président" ("The President").

After France failed to qualify for the 1994 FIFA World Cup, Blanc was heavily criticised, as well the rest of the team, and he subsequently decided to retire from international football.

Aimé Jacquet, after taking over the managerial position of the national team, made it one of his priorities to convince Blanc to change his mind.

Blanc scored France's opening goal in the final group match against Bulgaria in a 3–1 win to put the team into the quarter-finals, where they faced the Netherlands at Anfield.

In the quarter-final, Blanc helped France to a clean sheet over Italy and scored the winning penalty as Les Bleus prevailed in the shootout.

Blanc was also part of the team that won UEFA Euro 2000 during which, despite having been criticised for his age and lack of speed during the qualifications, he proved reliable in defence and even scored France's first goal of the tournament against Denmark in the group stage.

On 2 September 2000, Blanc, along with Deschamps and Bernard Lama, played his final match for Les Bleus in a friendly against England at the Stade de France.

The France national team was unbeaten in all matches when it fielded the World Cup and European Championship winning defence of Blanc, Desailly, Lilian Thuram and Bixente Lizarazu.

In 1999, the readers of France Football magazine voted him the fourth-best French player of all time, behind Michel Platini, Zinedine Zidane and Raymond Kopa.

In the 2009–10 Champions League campaign, Blanc's Bordeaux topped a group featuring Juventus and Bayern Munich without losing a match.

After resigning from his position, Blanc contacted the French Football Federation (FFF) to inquire about the France national team job, which was eventually vacated by Raymond Domenech following the 2010 World Cup.

[27] However, Blanc's team soon managed to top their Euro 2012 qualifying group while also achieving friendly wins over England, Brazil and Germany.

[29] On 3 August, Blanc won his first trophy with the club, the 2013 Trophée des Champions, defeating Bordeaux 2–1 in the Stade d'Angondjé in Libreville, Gabon, coming from behind with late goals from Hervin Ongenda and Alex.

[30] A second item of silverware was won on 19 April 2014, as two goals from Edinson Cavani defeated Lyon 2–1 in the 2014 Coupe de la Ligue Final.

[32] On 7 May 2014, after nearest rivals Monaco drew with Guingamp, PSG won the league, despite losing to Rennes later that day in the match in which they celebrated their triumph.

[33] The following day, Blanc was given a one-year contract extension to 2016, with club President Nasser Al-Khelaifi saying: "We are very happy with his results this season, as well as the very attractive football the team has played.

Blanc was criticised by the French media after the Champions League quarterfinal second-leg match against Manchester City, where he had surprised many by having his team play in an untried 5–3–2 formation that backfired completely.

[45] On 13 July 2024, Blanc was appointed as the head coach of Saudi Pro League club Al-Ittihad, replacing Argentine Marcelo Gallardo.