(AP Photo/Jae C. Hong)
"Newt is not running," spokesman Rick Tyler said. "It is legally impermissible for him to continue on as chairman of American Solutions [for Winning the Future] and to explore a campaign for president."
Gingrich, 64, decided "to continue on raising the challenges America faces and finding solutions to those challenges" as the group's chairman, Tyler said, "rather than pursuing the presidency."
Over the past few months, Gingrich had stoked speculation he might enter the crowded GOP field, despite the seemingly insurmountable challenge of entering the race several months after the other Republicans have been running.
He noted that GOP voters, especially conservatives, remain unhappy with the candidates and acknowledged that the much-anticipated entry of former Tennessee Sen. Fred Thompson into the race had been bumpy.
Yet he also has spoken positively of Thompson and the other leading contenders, including former New York Mayor Rudy Giuliani, former Massachusetts Gov. Mitt Romney and Arizona Sen. John McCain.
Just last week, Gingrich said he had given himself a deadline of Oct. 21 to raise $30 million in pledges for a possible White House bid, acknowledging the task was difficult but not impossible.
He abruptly dropped the idea Saturday, apparently unwilling to give up the chairmanship of American Solutions, the political arm of a Gingrich's lucrative empire as an author, pundit and consultant.
American Solutions, a tax-exempt committee he started last October, has paid for Gingrich's travel and has a pollster and fundraiser on staff.
Gingrich quit Congress in 1999 when his party lost seats in the 1998 elections.