Mutu started his career playing two years for Argeș Pitești and half a season for Dinamo București, before joining Inter Milan in Italy midway through the 1999–2000 Serie A.

After the 2006 Italian football scandal and the relegation of Juventus to Serie B, Mutu decided to join Fiorentina, where he played consistently for the next five years.

A controversial figure off the field, Mutu received widespread attention following a positive test for cocaine while playing for Chelsea in 2005, which resulted in his immediate release from the club, a subsequent seven-month ban from the Football Association, and Mutu later being ordered to pay £15.2 million in damages to his former employers, the largest financial penalty in FIFA history.

From his international debut in 2000, Mutu played 77 matches for the Romania national team and scored 35 goals, a joint record alongside Gheorghe Hagi.

(€2,633,930)[9][11][12] On 12 August 2003, Chelsea paid Parma €22.5m (around £15.8m) for Mutu's transfer as part of new owner Roman Abramovich's spending spree, on a five-year contract.

[17] In the 2004–05 season, Mutu had a difficult relationship with the club's new manager José Mourinho, with each accusing the other of lying about whether the player was injured for a 2006 World Cup qualifying match against the Czech Republic.

[15][20] The Football Association Premier League Appeals Committee decided that the player had committed a breach of his contract without just cause[15] which made Chelsea eligible to claim the compensation.

[28][29] In 2013, FIFA DRC decided in a new ruling that Livorno and Juventus were also jointly liable to pay compensation; both clubs immediately appealed to the Court of Arbitration for Sport.

[30] On 21 January 2015 the Court of Arbitration for Sport annulled the FIFA DRC ruling; Mutu remained the sole party to pay the compensation.

[41] After such events, Mutu publicly apologised to the club and parted company with his agent Victor Becali;[42][43] on 3 February 2011 Fiorentina announced the player was reinstated into the first team with immediate effect.

He said that he favoured the Italian culture on Corsica, dismissed claims that he was preparing for retirement, and stated that he would score more goals than Zlatan Ibrahimović of Paris Saint-Germain.

Club president Alain Orsoni said that Mutu was the highest-profile player to come to Corsica since Johnny Rep joined SC Bastia in 1978.

[50] In the summer of 2014, Mutu scored both home and away against Viktoria Plzeň in the UEFA Europa League third qualifying round, a double which Petrolul impressively won 5–2 on aggregate.

[52] On 30 July 2015, Mutu signed as the marquee player for Indian Super League club FC Pune City.

[53] In January 2016, Mutu returned to Romania with ASA 2013 Târgu Mureș, having been assured by national manager Anghel Iordănescu that he could have a place in the UEFA Euro 2016 squad if he played in a better league than India's.

[56] Since 2009, Romania's national team coach Răzvan Lucescu has had reservations about calling him up, because Mutu was revealed to be consuming alcohol after a match with Serbia in World Cup 2010 Qualifications.

On 21 November 2013, Mutu was barred from playing on the national team after he posted an image of manager Victor Piţurcă as Mr. Bean on Facebook.

Often compared to compatriot Gheorghe Hagi, in his prime, Mutu was a quick and mobile player, with excellent technical skills and dribbling ability, and was also an accurate set-piece and penalty-kick taker.

Despite his talent, he was often prone to injury and accused of inconsistency throughout his career, and was also notorious for his temperamental character and behaviour on the pitch; because of this, he was often regarded as not having lived up to his true potential.

[66] In July 2018, Mutu was signed by United Arab Emirates club Al Wahda to be the manager of their reserve team.