The veteran infielder will be joining Chicago for its World Series push.
The Cubs bolstered their lineup on Tuesday by acquiring infielder Daniel Murphy off waivers from the Nationals.
The waiver claim by the Cubs was first reported by Craig Mish of Sirius XM.
On Monday, it was reported that Murphy had been claimed off revocable waivers by an unnamed team. The Nats and Cubs then had 48 hours to agree on a trade. If no deal could be reached, Washington had the choice of either losing Murphy without receiving anything in return or pulling him back off waivers.
Cubs prospect Andruw Monasterio is being sent to Washington in the deal, according to MLB Network's Jon Heyman.
Murphy, a veteran, is no stranger to October baseball. He has hit eight home runs in 24 postseason games. In 2015, he became the first player in MLB history to homer in six consecutive playoff contests.
Murphy, 33, missed the Nationals' first 63 games this season while recovering from microfracture knee surgery. He entered Tuesday batting .300 with six home runs and 29 RBIs in 56 games since returning in June.
In 2016, Murphy joined the Nationals on a three-year, $37.5 million deal after helping the Mets reach the World Series in 2015. The Cubs will be on the hook for the remainder of his contract, which is about $4 million, according to The Athletic's Ken Rosenthal.
Murphy, a three-time All-Star, will become an unrestricted free agent at the end of this year.
The Nationals dealt more of their infield on Tuesday afternoon, shipping first baseman Matt Adams to the Cardinals.