The 19-year-old midfielder, who has been compared to Andrea Pirlo by PSG boss Carlo Ancelotti, was unveiled to the media on the same day as the French club's more headline-grabbing acquisition.
Verratti moves to the Parc des Princes from Pescara, who won promotion to Serie A last season, for an initial fee of £8.6 million which could rise to £11.75m.
"The players here are great champions," Verratti said. "I've seen them on television and now I'm training with them. It gives me a huge desire to do well here.
"It doesn't happen every day that a young player can join a great club like this. I'll do my best to repay PSG's faith in me."
The Italy Under-21 international, whose impressive displays in Serie B last term earned him a call-up for the provisional Euro 2012 squad, shows that big-spending PSG are planning for the future as well as the present with their signings, according to club president Nasser Al-Khelaifi.
"We are very happy to announce the transfer of Marco Verratti," said Nasser Al-Khelaifi. "He's young and we believe he's the future of Italian football.
"We hope he'll have a big impact at PSG. He's young and talented and we expect a lot from him in the future."
Verratti joins Argentina forward Ezequiel Lavezzi, Brazil centre-back Thiago Silva and Sweden striker Ibrahimovic in arriving at PSG, who finished second in Ligue 1 to surprise champions Montpellier last term.