Belletti began his career in the Campeonato Brasileiro Série A with Cruzeiro, São Paulo and Atlético Mineiro, being awarded the Silver Ball by Placar for his performances on loan at the last of those clubs during the 1999 season.

[citation needed] In March 1996, he was involved in a deal that sent him and Serginho to São Paulo FC in exchange for five players: Aílton, Donizete, Gilmar, Palhinha and Vítor.

[citation needed] After returning to São Paulo, he became a regular in the Brazil national team by playing in the right-back position once again.

[citation needed] In June 2002, prior to winning the World Cup with Brazil, Belletti moved to Spanish La Liga club Villarreal on a five-year deal for an estimated fee of US$3 million.

[5][6] He made his debut on 21 July in a 2–0 loss at Torino in the UEFA Intertoto Cup first round, playing the final 21 minutes in place of Jorge López.

[15] He made his Premier League debut two days later as a 64th-minute substitute for Mikel John Obi in a 4–0 home win over Portsmouth, a 4–0 victory.

[17] In his first season at Chelsea, Belletti scored two goals, both from long-range, the first away at Wigan Athletic in November and the second at Stamford Bridge against Tottenham Hotspur on 12 January 2008.

[18] On 21 May, in the 2008 Champions League final against Manchester United at the Luzhniki Stadium in Moscow, he came on as a substitute just before the penalty shoot-out,[19] in which he scored though his team lost.

[24] On 27 February, he was sent off for a professional foul on Manchester City midfielder Gareth Barry to concede a penalty in a 4–2 loss at Stamford Bridge.

[26] On 9 June 2010, Chelsea announced that Belletti was one of three players whose contract would not be renewed at the end of the month, alongside Joe Cole and Ballack.

[37] On 31 July, he was in charge of the club's first team trainings after the departure of Mozart,[38] but returned to previous duties on 3 August after the appointment of Vanderlei Luxemburgo.