The former PSG midfielder admits he was close to joining Juve 12 months ago.
"My aborted transfer last summer? Maybe PSG did not want to sell me, but better late than never," said Matuidi.
"I am very happy to be here. My teammates? Each team is different, each team has its own culture. An ambitious challenge will take shape.
"I was welcomed by my teammates and it will be easier to be on the ground."