Greene is the 186th wealthiest person in the U.S., according to Forbes, which estimated his net worth at $3.8 billion.
Greene, a Palm Beach real estate investor, will join a packed Democratic field that already features Tallahassee Mayor Andrew Gillum, former congresswoman Gwen Graham, Winter Park businessman Chris King and former Miami Beach mayor Philip Levine.
Greene, who lost a 2010 Democratic primary for U.S. Senate, told The Palm Beach Post in April that he has concerns about whether the four Democrats in the race — Tallahassee Mayor Andrew Gillum, former U.S. Rep. Gwen Graham, Winter Park businessman Chris King and former Miami Beach Mayor Philip Levine — will have the money and message to win in November.
Democrats have not won a Florida governor’s race since the late Lawton Chiles’s re-election over Republican Jeb Bush in 1994.
The qualifying period for gubernatorial candidates ends at noon on June 22. The Republican and Democratic primaries are Aug. 28.