The former Red Sox right-hander adds to the World Series pedigree at the back of the Cubs' relief rotation. He is expected to set up for closer Wade Davis, who recently was acquired from the Royals for outfielder Jorge Soler.
Uehara was on the mound for the final out of the 2013 World Series, while Davis closed out the 2015 series for Kansas City.
Uehara was the American League Championship Series MVP in 2013 and recorded a record-tying seven postseason saves that year. During that regular season he was 4-1 with a 1.09 ERA and allowed just 33 hits and struck out 101 in 74 1/3 innings while recording 21 saves.
He was 2-3 with a 3.45 ERA and 63 strikeouts against 11 walks in 47 innings last season.
Uehara was named an All-Star in 2014, has participated in two Olympics and helped Japan win the World Baseball Classic title in 2006.
Uehara began his major-league career with the Orioles in 2009 before he was traded to the Rangers in 2011.
The Cubs brought in Uehara and Davis to help bolster a bullpen that lost closer Aroldis Chapman to the Yankees in free agency and are expected to lose left-handed free agent Travis Wood.
With Uehara's signing, the Cubs have pitchers who have recorded the final out in three of the last four World Series. Left-hander Mike Montgomery accomplished the feat in early November to help the Cubs to their first title since 1908.