Chiellini was a free agent when he lifted the Euro 2020 title as a captain for Italy.
The 36-year-old's 16 years at Juventus has won him 14 major trophies including nine consecutive Italian league titles between 2011-12 and 2019-20.
After Chiellini signed the new deal, Juventus disclosed the news with a statement;
"He forms a big part of Juve's history, yet also the present and the future.
"Giorgio Chiellini embodies everything that Juventus stands for, and it is through his commitment and excellent displays over the course of the last 16 years that has earned him a contract renewal.
"There is an overlap in Giorgio's DNA and that of Juve's".
Signing a new deal means Chiellini will spend 19 years at Juventus if he's able to play out his contract with the club.
The Euro 2020 winner was delighted to have committed his future to Juventus.
"Best not to think about that, it’ll make me feel even older. Chiellini said on Juventus TV.
"I am happy, even if it seems like a formality, these are important steps in life. I arrived here barely an adult and now I’m part of the family, a mature person who is enjoying every moment of the last years.
"I really hope that I can give my contribution and help this team to win more titles, which as we know here is the most important thing.
"In the end the signing was a formality, because as soon as I knew that my body would allow me to continue playing, there was always the will of both parties to continue together.
"It was just the timing of various situations that delayed this signing.
"The very close relationship between myself and Juventus goes beyond everything else. I had absolutely no doubts that I would remain here."
