Buffon apparently only wanted a one-year extension with the club offering three years, but both parties have settled on the middle ground.
"I remember my first day and the fact that I was asking myself if I was up to the standard of a club like Juventus," Buffon told a news conference in Turn.
"My rapport with the fans has been important. I also enjoy a good relationship with the management and coaching staff.
"I would have turned down offers from other teams. For me Juventus has become a way of life.
"Above all I would like to win the trophies that have eluded me in my career so far. Starting with the Champions League.
"We want to reclaim the Italian title. We've shown we're back as a competitive force in Europe. That's what matters."
Juventus president Andrea Agenell commented that he was thrilled to extend the contract of Buffon. He hopes that Buffon will be named Europe's best player within the next two years.
He said: "Gigi is our captain and today has signed a contract that ties him with the club for a further two years. Just one quick glance was enough for us to come to an agreement and decide to carry on.
"Buffon is sincere, loyal, honest and constructive. Juventus is Gigi's home. I hope that in the next two years Gigi will be able to bring the Ballon d'Or back to Italy."
Buffon's agent Silvano Martina said: “There were never any problems regarding the extension.
“The fact that an agreement was reached with Juventus has been known for some time.
“All that we needed to agree on was a formula – the club wanted to give him a three-year deal and he wanted a one-year one. In the end a two-year renewal was agreed.”
Buffon has apparently accepted a 1.5m cut to his 6m euro a year deal.
“Gigi understood the needs of the country and accepted to take a small adjustment to his salary,” said Martina.