Forte, the second-most productive running back in franchise history, spent eight seasons with the Bears, rushing for 8,602 yards and scoring 64 total touchdowns.
Forte, who turned 30 in December, earned a base salary of $7.050 million last season. He led the Bears in rushing with 898 yards on 218 carries and caught 44 passes for 389 yards while scoring seven total touchdowns.
"Despite my wishes, my days as a member of the Chicago Bears have sadly come to an end," Forte wrote on Instagram. "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. God Bless and Bear Down!"
The Bears later confirmed they would not re-sign Forte, who 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. "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 had 12,718 yards from scrimmage with the Bears -- rushing for 8,602 yards and hauling in 4,116 receiving yards. He ranks second in franchise history in yards from scrimmage, rushing yards, receptions (487), 100-yard rushing contests (24) and games with 150 yards or more from scrimmage (25), trailing only Hall of Famer Walter Payton in all five categories.
Forte's versatility puts him in elite company with Payton as his eight seasons with 1,200 yards from scrimmage in a Bears uniform are second only to Payton's 10.
Forte, a Pro Bowl selection in 2011 and 2013, leads the NFL in yards from scrimmage and games with 150 or more yards from scrimmage since entering the league in 2008. In 2014, he broke the NFL single-season mark for receptions by a running back with 102 and set the franchise single-season running back record for receiving yards (808) that year.
Forte is one of 12 players in NFL history with 8,000 career rushing yards and 4,000 career receiving yards and is one of five players in league history to have 1,200-plus yards from scrimmage in each of his first eight seasons.
A team-captain in 2015, Forte is a two-time recipient of the team's Brian Piccolo Award (2008 and 2014), the team's 2015 Walter Payton Man of the Year nominee and was one of eight NFL finalists for the 2015 Art Rooney Sportsmanship Award.