The Marlins reached an agreement with Marmol last Thursday, pending the completion of his physical.
To make room on the 40-man roster, reliever Chris Hatcher was designated for assignment.
Marmol will look to carry over the effectiveness he showed while pitching for Licey this winter in his native Dominican Republic.
During the Caribbean Series, which concluded on Friday in Venezuela, Marmol tossed two perfect innings, striking out two, and, more important, walking zero. On Wednesday, against Mexico, he threw an eight-pitch inning, including seven strikes. Marmol's fastball that night was clocked between 94-96 mph.
For Marmol to enjoy success with the Marlins, he must rein in the command of his blazing fastball and lively slider.
Marmol is an experienced closer, having compiled 117 saves in parts of eight seasons with the Cubs. He was traded from the Cubs to the Dodgers last season, and combined for a 2-4 record and a 4.41 ERA. Marmol recorded five wild pitches in 2013 and has 33 in his career. In addition, he misses plenty of bats, as reflected by his 730 strikeouts over 504 games.
In recent weeks, the Marlins coveted a veteran with big league closing experience as insurance for Steve Cishek, who converted 34 of 36 chances last season.
Marmol is in the mix to set up Cishek, and he will compete for a late-inning role with right-handers A.J. Ramos and Carter Capps.
Pitching in the Caribbean Series gave Marmol some game experience heading into Spring Training, which opens for Miami on Sunday at the Roger Dean Stadium complex in Jupiter, Fla.
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.