Bastian Schweinsteiger says he is excited by the "vision" at Chicago Fire after the MLS side confirmed he has accepted a one-year contract.
Manchester United announced earlier on Tuesday that the former Germany captain will move to the United States subject to the completion of a medical and the successful acquisition of a visa.
Fire later confirmed that the 32-year-old has finalised his transfer to Toyota Park as a Designated Player, which means he will not be subject to the division's salary cap.
"Throughout my career, I've always sought opportunities where I hoped to make a positive impact and to help make something great. My move to Chicago Fire is no different," Schweinsteiger told the club's official website.
"I'm convinced by the club's vision and philosophy and I want to help them with this project."
"This is a historic moment for our club," said Fire general manager Nelson Rodriguez. "We have added one of the greatest champions in all of sports. Bastian's talents, attitude, and character will be a perfect complement to our squad as we continue building a championship programme."
Head coach Veljko Paunovic added: "Having the strongest possible midfield is essential for how we want to play. We see Bastian helping our organisation of the attack, and impacting the final third build-up with his vision and creativity to produce the final pass, as well as his capacity to score goals.
"His versatility on the field, and his immense experience at the highest levels of this sport will be a great benefit to our team."