In his club career, Diarra played for Chelsea, Arsenal, Portsmouth, Real Madrid and most recently Paris Saint-Germain before retiring in 2019.

Diarra was spotted by Gwyn Williams[9] playing for France in the 2005 Toulon Tournament and initially came on trial, before the club paid £1 million for his services in July 2005.

Learning from Claude Makélélé he played well against Huddersfield Town in the FA Cup third round, winning rave reviews from both managers, teammates, and media sources.

On his move across London, he cited Gunners manager Arsène Wenger as one of the main reasons for joining the club, along with the style of football played by Arsenal.

[17] With the emergence of defensive midfielder Mathieu Flamini in the Arsenal side, Diarra saw only limited action in the early months of the season.

Having expressed concerns that he was not playing enough first team football,[18] Diarra signed for Portsmouth in January 2008 after only five months at Arsenal for an undisclosed fee believed to be around £5.5 million.

[24] Diarra went on to play in every minute of Portsmouth's remaining FA Cup matches en route to claiming the trophy in the final.

[35] Diarra's performance for Real Madrid in his first few months earned him a spot among the starting eleven on UEFA's 2008–09 La Liga Breakthrough Team.

According to the UEFA website, he "joined Real Madrid in the winter transfer window with a very low profile, although in a few short months he managed to convince the demanding Madridista fan base."

It seems he was forced out of the club alongside fellow midfield enforcer Esteban Granero to accommodate the stay of Kaká, despite the latter being linked with an exit.

Despite being sent off twice in his first matches for his new club against Zenit Saint Petersburg and Tom Tomsk respectively, Diarra quickly established himself in starting eleven, claiming one of two usual holding midfielder's posts alongside Dmitri Tarasov.

In his first months at Lokomotiv, Diarra provided so many solid performances that someone even claimed that he was the strongest player in the history of the Russian Premier League.

It even sought damages from Diarra for breach of contract and managed to get FIFA to ban him from playing professionally for another club as long as his contractual dispute with it was not settled.

Diarra challenged these rules on the grounds that they violated his right to free movement within the EU, which allows workers to seek employment in other member states without restrictions.

[58] Following Rudi Garcia's appointment as new Marseille manager in October, however, Diarra's commitment to the club was questioned and he was later stripped of his captaincy in favour of loanee, Bafétimbi Gomis.

[60] Former manager José Anigo later claimed that the breakdown of relationship between club and player stemmed from then-chairman Vincent Labrune's failure to honour contractual promises to Diarra.

Perhaps his most notable performance came in the 2006 UEFA European Under-21 Championship qualification play-offs second-leg match against England at the Stade Marcel Picot in November 2005.

With the match several minutes from full-time and seemingly destined for extra time (the aggregate score was 2–2), he received the ball in the England penalty box, where a challenge from Kieran Richardson brought Diarra down.

[72] Diarra's consistent club performances in 2008 resulted in him being picked for the France squad for Euro 2008, ahead of high-calibre players such as Djibril Cissé and Mathieu Flamini.

[73][74][75] Following the international retirement of fellow defensive midfielder Claude Makélélé, Diarra was called up for Domenech's France squad in the 20 August 2008 friendly with Sweden.

On 22 May, however, while training with the national team in the high-altitude commune of Tignes, it was announced that Diarra was dropping out of the squad due to his suffering severe intestinal pain and stomach cramps as a result of the altitude.

[79] After an absence of over five years, Diarra received a surprise recall to the French team following a fine run of form at the beginning of the 2015–16 season.

Upon announcing his return to the squad, France manager Didier Deschamps highlighted Diarra's performances in a struggling Marseille side as the reason behind his inclusion.

[81] Despite being an aggressive, hard-tackling and hard-working player, Diarra has unusually good ball control for a defensive midfielder, and has been praised for his physical strength in defence, as well as his composure, and strong mentality.

[82][87][88] Due to his many attributes and versatility, Madrid's La Sexta television commentators refer to him as a "todocampista," or "jack of all trades",[89] and he has also occasionally played in more advanced midfield roles, or as a right back.