[6] According to his profile on the website of his former club Arsenal, Djourou possessed "pace, power and whole-hearted commitment" in addition to his versatility.

Djourou was born in Abidjan, Ivory Coast,[3][9] to Ivorian parents Joachim and Angeline, and was later adopted by his father's first wife, Danièle, a Swiss woman.

[20] Djourou made his full Premiership debut for Arsenal in the 7–0 victory over Middlesbrough on 14 January 2006, playing at centre-back with Philippe Senderos.

[23] After a five match absence, he returned to the first team, coming on as a substitute against Aston Villa in Arsenal's 5–0 victory, replacing the injured Emmanuel Eboué.

[30] Shortly after, however, he missed four matches, due to international commitment and competitions, he returned to the first team against Fulham on 29 November 2006, coming on as a 65th-minute substitute, in a 2–1 loss.

[40] Djourou continued to play for Birmingham consistently through his loan period until 22 December 2007, when he gifted Bolton Wanderers' Nicolas Anelka a goal via an errant throw-in.This marked his last appearance for the club.

Shortly after returning from a loan spell at Birmingham City, Djourou made his first Arsenal's appearance of the 2007–08 season, coming against Tottenham Hotspur in the semi-finals of the League Cup, and played 45 minutes before being substituted at half time, as they drew 1–1.

[46] Instead, he played in the centre of defence as first choice backup following the departure of fellow Swiss defender Philippe Senderos to A.C. Milan on a season-long loan.

[53] After missing two matches as a result, Djourou returned to the starting line-up against Plymouth Argyle in the third round of the FA Cup and helped Arsenal win 3–1.

[60] It was announced on 6 September 2009 that Djourou's recovery period would take an estimated of six to eight months; Arsène Wenger stated: "He will have to be patient this season.

[69] He played in both legs of the semi-finals against Ipswich Town to help Arsenal win 3–1 on aggregate to reach the Football League Cup Final.

[71] He, once again, helped the club's defence keep three consecutive clean sheets between 12 February 2011 and 5 March 2011 against Wolverhampton Wanderers, Stoke City and Sunderland.

[76] On 24 April 2011, against Bolton Wanderers at the Reebok Stadium, he conceded a penalty (missed by Kevin Davies) in a 2–1 defeat which effectively ended Arsenal's title hopes.

Local newspaper Islington Gazette gave Djourou's performance 8/10, saying: "Having missed over a year with a serious knee injury, his return coincided with a defensive shortage and he stepped into the breach admirably, not being on the losing side in the league until late April, when his form did start to fade.

[81] Three days later Arsenal announced the signing of experienced German defender Per Mertesacker from Werder Bremen, and Djourou's first team opportunities became more limited in the centre-back position.

[83] Despite being involved in the first team, Djourou, at times, found himself out of the starting eleven, due to competitions that saw him placed on the substitute bench and his own injury concern.

[85] After serving a one match suspension, Djourou returned to the starting line-up against Swansea City on 15 January 2012, and set up Arsenal's second goal of the game, in a 3–2 loss.

Ahead of the 2012–13 season, Djourou was told by Manager Ottmar Hitzfeld that he must leave Arsenal in hopes of getting a call up from Switzerland.

"[94] On 3 January 2013, Djourou confirmed that he was set to move to Bundesliga club Hannover on loan until the end of the season, with no option to buy included in the deal.

[97] Djourou then helped Hannover 96 keep two consecutive clean sheets between 30 March 2013 and 7 April 2013 against FC Augsburg and VfB Stuttgart.

[99] It wasn't until the last game of the season against Fortuna Düsseldorf when Djourou returned to the starting line-up and kept a clean sheet, in a 3–0 win.

[103] It wasn't until on 31 August 2013 when he made his debut for the club, starting the match and played 72 minutes before being substituted, in a 4–0 win against Eintracht Braunschweig.

[113] Despite this, Djourou returned to the first team and played in both legs of the relegation play-off matches against Greuther Fürth, where a 1–1 draw kept Hamburg retaining their Bundesliga status via an away goal.

[115] As the 2013–14 season was coming to an end, Hamburg confirmed on 2 April 2014 that they had activated the buying clause and signed Djourou on a permanent deal.

[125] After serving a one match suspension, Djourou returned to the starting line-up against FC Augsburg on 25 April 2015 and helped the club win 3–2.

[126] He then played in both legs of the relegation play-off matches against Karlsruher SC, as Hamburg won 3–2 on aggregate to retain their Bundesliga status.

[145] By the second half of the season, Djourou's first team opportunities soon became limited, due to his own injury concerns and competitions that saw him placed on the substitute bench.

On transfer deadline day, 5 October 2020, Djourou joined Danish Superliga club FC Nordsjælland on a two-year deal.

My biological mother still lives there and I have a lot of contact by telephone with my family there, so if I am picked to play for Switzerland against my 'other country' it is sure to be a special moment.

[204] Following the conclusion of the World Cup, Djourou kept four clean sheets for the national side between 14 October 2014 and 10 June 2015 during his playing time in Switzerland's four of the six matches.