The 33-year-old France international has struck a deal with the Serie A champions allowing him to leave for free before his contract ends.
Matuidi spent three seasons in Serie A after joining Paris Saint-Germain, winning the Italian title every year and proving an important part of the Juventus squad throughout his time at the club.
In all, he made 133 appearances for Juve, also winning the Coppa Italia and Supercoppa Italiana – as well as the World Cup with France in 2018.
During his time at the club, Paulo Dybala was the only player to make more appearances for Juventus.
It underscores his status at the club and perhaps gives an indication of the level Miami expects from him.
As Matuidi turned 33 in April, he made 45 appearances for Juve in 2019-20 and the MLS side are hoping to have signed a midfielder still close to the peak of their game.
Head coach Diego Alonso will no doubt be eager to make him part of his squad as soon as possible, with Miami having lost all six of their games so far.
They suffered five losses in the MLS regular season and the MLS is Back tournament, all by one goal.
Juventus wished Matuidi a farewell in their official statement, which said: “It was above all his substance in the midfield that made the difference and made him a much loved player by Juventus fans: for his determination, for his guts and for his ability to never give up.
“And it is because of all these characteristics, and for the great commitment that he has always put in place with us, that we thank him.
“Blaise is someone who will always be in our hearts and we wish him the best for the future.”
Before his stint at Juventus, Matuidi had spent his entire career in France with PSG, Saint-Etienne and Troyes.