Marty Markowitz says he is only in the process of deciding whether to run for mayor, but he is sure sounding a lot like a candidate.

From a horseshoe-shaped booth at Junior’s restaurant in downtown Brooklyn, Mr. Markowitz, the silver-haired career politician who as president of Brooklyn is known as the borough’s most enthusiastic cheerleader, offered up policy positions and a potential campaign motto (“Keep it safe, keep it clean, keep it working”) — clues to what the city might look like under Mayor Marty.

If Mayor Bloomberg’s congestion-pricing plan is approved, the irrepressible Mr. Markowitz says he wants Manhattan car owners to pay a penalty, arguing it is only fair that those on the densely packed island be charged for the luxury and convenience of owning a car.

He is promising to push for broader rent regulations and says he supports keeping mayoral control over the public schools, but would give parents and teachers more influence in decision-making.

He is suggesting that Washington lawmakers be urged to designate New York City a national city and create a special funding source for it, and said his administration would look, in many ways, like the one crafted by Mr. Bloomberg.

“Competence, pragmatism as opposed to ideology. Doing what’s right for New York without kowtowing to special interests and competency above all,” he said.

Mr. Markowitz, who says he has Brooklyn in his DNA, even said he’d be willing to leave his beloved borough if elected and install himself in Gracie Mansion with his wife. He does have one caveat: “I wouldn’t mind living in Manhattan — but living in Brooklyn on the weekends,” he said during an interview with The New York Sun.

In most political circles, Mr. Markowitz’s daydreams about running for mayor and winning have been dismissed as just that — dreams. Skeptics, though, may not want to discount the possibility that Brooklyn’s most vocal promoter could enter the race and emerge as a serious contender.

After being left out of news reports and conversations centering on the leading mayoral candidates, Mr. Markowitz turned political heads in February when he led a poll of likely Democratic candidates for mayor.

He picked up support from 18% of Democratic voters asked in a WNBC/Marist poll which possible Democratic candidates they’d support if the 2009 mayoral primary were held that day.

Rep. Anthony Weiner came in second, with 13%. The speaker of the City Council, Christine Quinn, was at 11%, and the city comptroller, William Thompson Jr., and the public advocate, Betsy Gotbaum, each got 9%.

Mr. Markowitz said he was flattered by the attention, but dismissed the poll as a limited snapshot of the public’s thinking, which he said offered little indication of the city’s political future. His strong showing caught Mr. Bloomberg’s eye, and the mayor took it as an opportunity to give his potential successor a boost.

“He’s a character,” Mr. Bloomberg told reporters after the poll was released. “Bloomberg’s a character, Giuliani was a character, Dinkins was a character, Koch was a character, Beame was a character, Lindsey — I mean Marty Markowitz follows in a grand tradition and there’s no reason why he couldn’t be another one in a series of characters.”

Mr. Markowitz, 63, grew up in Crown Heights and is a graduate of Wingate High School and Brooklyn College. He began his career as a tenant organizer and spent more than 20 years representing central Brooklyn in the state Senate before winning the Brooklyn presidency in 2001.

Being elected president of Brooklyn was the fulfillment of a nearly lifelong dream that began when he visited Borough Hall on a school trip at the age of 16 and met President Abe Stark.

As Mr. Markowitz deliberates whether to attempt to tack another chapter onto his lengthy political career, he said it helps that he already has achieved his primary professional goal. He admitted that running for mayor would be impossible without a key factor that helped him with the presidency.

“You have to have the passion. You have to have the heat,” he said. “When I ran for borough president, I had the heat. And at this time, I still don’t have the heat.”

As of January 15, Mr. Markowitz had raised about $901,000 for a political campaign, according to the city’s Campaign Finance Board. Mr. Thompson had raised about $4.2 million, Mr. Weiner about $3.6 million, and Ms. Quinn nearly $2.5 million.

He’s been meeting with city leaders to talk about a potential run, and said that while some tell him he’d be out of his mind to run, others have said he has nothing to lose.

A run for mayor, however, could galvanize New Yorkers opposed to the Atlantic Yards development in downtown Brooklyn that Mr. Markowitz has trumpeted.

A spokesman for Develop Don’t Destroy Brooklyn, Daniel Goldstein, said his organization “would look forward to a Markowitz mayoral run as it would make certain the failing Atlantic Yards project and the other egregious overdevelopment he has overseen in Brooklyn would be major issues in the race, as they should be.”

Mr. Markowitz has said the project will bring affordable housing, in addition to a new city center and a professional basketball arena, to downtown Brooklyn. He appears to get as excited as a boy on a first trip to an amusement park when envisioning attending the first Brooklyn Nets game in the new stadium.

Mr. Markowitz said one challenge he would undoubtedly face if he ran for mayor would be convincing New Yorkers that he is not just a candidate for Brooklyn, but for the whole city. He said he is the potential candidate most strongly linked to a single borough, but to show that he is ready to look out for New Yorkers no matter where they live, he explained that the city’s boroughs are like five children in a family.

“Each child has to be treated with the same love, and that’s it,” he said. “Now if you ask me my preference, of course, you always love – most families love their first child a little bit more.”

“It’s not uncommon, by the way,” he said. “It’s not uncommon.”