The Brazilian defender has put pen to paper on a five-year deal with the French giants after negotiations between the two clubs finally reached a conclusion on Saturday
The Brazil international, 27, had been linked with a move to the Parc des Princes throughout the summer, and he has now made the switch to the French capital, where he is expected to be joined by his former Milan team-mate Zlatan Ibrahimovic.
He has agreed a five-year contract worth a reported €7.5m per year, including €1.5m in bonuses, and becomes the second most expensive defender in the world after Manchester United centre-back Rio Ferdinand.
After previous failed spells in Europe with Dynamo Moscow and Porto, Thiago Silva returned to the continent from Fluminense in 2009 and lifted the Serie A title in only his second season at San Siro.
Although the side were unable to retain their Scudetto crown the following campaign, he appeared to have committed his long-term future to the Rossoneri, having penned a five-year extension at the end of June.
However, with Milan's financial problems well documented, president Silvio Berlusconi confirmed that he had accepted a bid from PSG in the region of €65 million for both the Brazilian and Ibrahimovic, despite the Ligue 1 runners-up seeing an initial bid for the stopper rejected.
But while the deal to bring in the Swede remains incomplete, Thiago Silva is now officially a PSG player and will join up with former coach Leonardo, as well as many ex-Serie A rivals, including Thiago Motta, Javier Pastore and Ezequiel Lavezzi.