Both clubs have confirmed the news, with the veteran German expected to link up with Veljko Paunovic's side next week after signing a designated player contract that guarantees him $4.5 million in 2017, according to the Chicago Tribune.
"Throughout my career, I've always sought opportunities where I hoped to make a positive impact and to help make something great," Schweinsteiger said in a statement released to the Tribune.
Auf Wiedersehen, Basti... pic.twitter.com/oFhB49ykze— Goal (@goal) March 21, 2017
"My move to Chicago Fire is no different. Through my conversations with [general manager Nelson Rodriguez] and Pauno, I'm convinced by the club’s vision and philosophy and I want to help them with this project."
Schweinsteiger has been scarcely used under Jose Mourinho at Old Trafford this season, featuring in just four matches in all competitions and not making any Premier League appearances. His most recent outing came in a Europa League match against Saint-Etienne on February 22.
Before joining United in July 2015, Schweinsteiger had spent his entire professional career with Bayern Munich. His trophy-laden spell with the club from 2002 to 2015 included eight Bundesliga titles and the 2012-13 UEFA Champions League crown.
The 32-year-old retired from international duty last summer, making his final appearance in a friendly against Finland on August 31 after playing five matches at Euro 2016. The deep-lying playmaker finished his international career with 24 goals in 121 caps, including six appearances as Germany won the 2014 World Cup.
"We're adding someone who has won at every level, including the very highest levels, and has done so in a way that is consistent with our values," Rodriguez said.
"We as a club will now be forced to hold ourselves to a higher standard, an accountability level. Previously, I think we could satisfy ourselves with what is known domestically. Now we need to rise to a standard that is set more internationally."
Paunovic added: "In the locker room, he will be a huge example of a champion. He still is somebody that can show that on the field and [demonstrate] how our guys have to work, prepare, behave, think and work together in order to get to that level."
The German joins a revamped Fire team that already had added U.S. international Dax McCarty, former LA Galaxy standout Juninho and Hungary international Nemanja Nikolic since finishing at the bottom of the MLS standings last season.
Schweinsteiger's signing comes four months after he was spotted sharing lunch with Paunovic in Manchester, with the Fire coach now revealing they spoke for hours about a potential move.
"The conversation was so spontaneous, so natural and so inspiring for both sides," he said. "At one point it became a very personal conversation. I think that also helped for both sides to understand how we can help each other and how much value we can get from this for both sides."