The deal for the 36-year-old is for one year. Financial terms were not announced, but a source confirmed Furcal will make $3 million, plus incentives.
There is some risk to the signing because Furcal missed all of 2013 due to Tommy John surgery on his right elbow.
Considering his track record and years of big league success, the Marlins are comfortable that Furcal will be a big acquisition.
The veteran became a key part of the Cardinals' World Series championship team in 2011. He last appeared in the big leagues in 2012, when he played in 121 games for St. Louis.
The Furcal announcement comes hours after the Marlins made it official that they signed former Red Sox catcher Jarrod Saltalamacchia to a three-year contract.
Like Saltalamacchia, Furcal has been part of a World Series winner.
Furcal broke in with the Braves in 2000, and he went on to be the National League Rookie of the Year. In 2006, he signed as a free agent with the Dodgers, and he was dealt to St. Louis during the 2011 season.
With Adeiny Hechavarria at shortstop, the Marlins are asking Furcal to move to second base, a position he last played in the big leagues with the Braves in 2004. That year, he saw action in just one game at second. Two years earlier, he played in just four games at the position.
A switch-hitter, Furcal has a career .281 batting average with a .346 on-base percentage. Furcal is a candidate to lead off for Miami, which ranked last in the Majors in runs scored and home runs last season.
Among active players, Furcal ranks 17th in runs scored with 2000, and he is sixth in stolen bases with 314.
The arrival of Furcal means the Marlins will either use Donovan Solano in a utility role or move him to third base.
Joe Frisaro is a reporter for MLB.com. He writes a blog, called The Fish Pond. Follow him on Twitter @JoeFrisaro. This story was not subject to the approval of Major League Baseball or its clubs.