[4] Having been bought by the Premier League club Chelsea in 2004, Alex was loaned to Dutch team PSV and he won 3 Eredivisie titles with them.

He joined Paris Saint-Germain for £4.2 million in January 2012 and won Ligue 1 twice with the club, moving to A.C. Milan on the expiration of his contract in 2014 and retiring two years later.

Alex earned 17 caps for Brazil between 2003 and 2008, winning the 2007 Copa América and finishing as runner-up at the 2003 CONCACAF Gold Cup.

Alex began his career with Santos of Brazil, making his first team debut in 2002 before later becoming part of the club's central pillars.

While playing for PSV, he earned himself the nickname "The Tank" due to his cannonball-like free kicks and his strong physical stature.

[3] He formally joined PSV in the 2004–05 season, helping the club win a domestic double of both the Eredivisie championship and Dutch Cup that year.

Alex scored in a UEFA Champions League first knockout round against Arsenal for both teams in the second half, turning in an own goal past his own goalkeeper Heurelho Gomes, but compensating for it with a storming headed goal with eight minutes left to play to redeem himself and in the process ensure PSV a place in the quarter-finals.

[14][15] On 14 August 2007, Alex was presented to the English media in a press conference with manager José Mourinho, where he was given shirt number 33.

[27] He started his first game of the season in a League Cup match against Bolton Wanderers on 28 October 2009, playing the full 90 minutes.

[28] On 13 March 2010, he scored his first goal of the season at Stamford Bridge giving Chelsea the lead in a 4–1 league win over West Ham United.

[29] In light of Ricardo Carvalho's departure to Real Madrid, Alex started the 2010–11 season as first-choice centre-back for Chelsea, alongside John Terry.

On 5 October, he was ruled out for up to three weeks after picking up a thigh injury in the final stages of Sunday's 2–0 win over Arsenal, and subsequently withdrew from the Brazil squad for the friendly matches against Iran, and Ukraine.

[32] After he recovered from the injury, Alex made his return on 9 April 2011 in a match against Wigan Athletic in a 1–0 win, where he came on for Paulo Ferreira in the 75th minute.

In the last league game of the season against Everton, Alex started the match alongside John Terry but was substituted on 70 minutes for Ferreira in their 1–0 defeat at Goodison Park.

On 21 September 2011, in a League Cup tie against Fulham, Alex received a straight red card in the 49th minute after a foul on Kerim Frei, which also resulted a penalty.

The move, however, broke down after both parties reportedly failed to agree personal terms; QPR could not match his wage demands and Alex stated he did not want to stay in England.

[citation needed] On 3 August 2013, Alex scored the game-winning goal with the last kick of the game in PSG's 2–1 defeat of Bordeaux in the Trophée des Champions at the Stade d'Angondjé in Libreville, Gabon.

[41] He made his competitive debut on 31 August in their first match of the new Serie A season, a 3–1 home win over Lazio in which he deflected Antonio Candreva's shot into his own net.

[43] On 25 May 2016, club owner Silvio Berlusconi announced his departure, along with those of Phillippe Mexes, Kevin-Prince Boateng and Mario Balotelli.