The announcement ended weeks of speculation that Bloomberg, an independent who is leaving office after 12 years, could endorse Republican nominee Joe Lhota in an attempt to thwart the rise of the mayor's frequent antagonist, Democratic front-runner Bill de Blasio.
"I don't want to do anything that complicates it for the next mayor and that's one of the reasons I won't make an endorsement in the race," Bloomberg said during his weekly appearance on John Gambling's show on WOR Radio.
"I'll leave campaigning to the campaigners," Bloomberg said. "But whoever the voters elect, I want to make sure that person succeeds."
A top Bloomberg aide confirmed on Twitter after the show that the mayor would not endorse anyone before the Nov. 5 general election. The decision could be a blow to Lhota, who has spoken of wanting the mayor's support.
The radio show marked Bloomberg's first comments about the election since Tuesday's primary. He did not speak publically on the anniversary of the Sept. 11 attacks and did not take questions from reporters Thursday after a speech about the World Trade Center rebuilding process.
He stressed to Gambling that he made his decision to sit on the sidelines of the race because he has "never been a partisan guy."
But Bloomberg also may have wanted to avoid a repeat of the firestorm that erupted after his last comments about the race. In an interview with New York magazine published last weekend, Bloomberg said de Blasio's campaign, which is based on solving income inequality, was a form of "class warfare" and was "racist," because the public advocate used his biracial family in commercials.
Several Democratic primary voters said the interview made them more committed to supporting de Blasio.
De Blasio has not yet secured the Democratic nomination. He is hovering around 40 percent of the vote that would avoid triggering an automatic runoff. On Friday, election officials will begin checking vote totals and will add absentee ballots on Monday.
The primary's second-place finisher, ex-comptroller Bill Thompson, has resisted calls to bow out in the name of party unity. He said late Thursday that he wants the vote-counting process to go forward.
Bloomberg did not endorse anyone in the primary but spoke favorably of City Council Speaker Christine Quinn, who finished third.
He likely would have had a significant impact on the general election had he jumped in. Though polling suggests voters are ready for a change, Bloomberg continues to hold fairly high job approval ratings and could have used some of his $27 billion fortune on a candidate's behalf.
___ Associated Press Writer Ula Ilnytzky contributed to this report.