"Despite my wishes, my days as a member of the Chicago Bears have sadly come to an end," Forte said in an Instagram post. "I was informed earlier this week from the GM that they will not be attempting to re-sign me in free agency.
"I will remain forever grateful for my time spent in Chicago and being able to play for an organization with such a rich history. My only regret is not being able to win a Lombardi trophy for the best fans in all of sports. I'm excited about the next chapter of my NFL career. But, Chicago will always be home."
The Bears later confirmed Forte's announcement on Twitter, saying they told the running back that they would not re-sign him. Forte will be a free agent when the new league year begins March 9.
"We recently met with Matt to inform him we will not extend a contract offer for the 2016 season," Bears general manager Ryan Pace said in a statement Friday. "These decisions are never easy, especially given what Matt has meant to our team and community. We have a tremendous amount of respect for him.
"Matt is one of the all-time great Bears and did an excellent job for us on and off the field last season. He was a tremendous teammate. We thank him for his professionalism and wish him the very best as he continues his career."
Forte, 30, spent eight seasons with the Bears, rushing for 8,602 yards and scoring 64 total touchdowns. As a team captain, he led the Bears in rushing last season with 898 yards and caught 44 passes for 389 yards while scoring seven total touchdowns.
He earned a base salary of $7.05 million with the Bears last season.
Pace had turned down Forte's request for an extension last offseason and appears ready to give a larger role in the offense to Jeremy Langford, who rushed for 537 yards and six touchdowns in 2015.
Forte ranks second, behind only Hall of Famer Walter Payton, on the Bears' all-time lists for rushing yards, yards from scrimmage (12,718), receptions (487) and 100-yard games (24). He's third in total touchdowns and sixth in receiving yards (4,116).
ESPN Staff Writer Jeff Dickerson contributed to this report.