Anthony Weiner came out of La Guardia Airport at an aggressive clip, his steps tight and agitated. Earlier that afternoon, after a single-engine plane nosed its way toward Washington, the Capitol was evacuated, setting the congressman back two hours. He had three stops on his mayoral campaign schedule that night, and chances were he wouldn’t make them all.

Once in the shotgun seat of his Ford Hybrid, he tore into the McDonald’s bag the aide who was driving the car had picked up for him. Another aide, who was in the backseat, had been assigned the task of picking up a straw for his boss. The McDonald’s bag contained a cheeseburger, a Filet-O-Fish sandwich, and a Coke. Mr. Weiner made a disgruntled face, turned to the kid at the wheel, and reminded him: “I said, ‘Do me a favor, get me a Mac, burger, fries, Coke.” The kid smirked and kept looking ahead at the road. Mr. Weiner continued, his voice adopting the automatic rhythm of somebody trying to memorize something right before an exam.” I said, ‘Get me a Mac, burger, fries, Coke. A Mac, burger, fries, Coke. Get me a Mac, burger, fries, Coke. Get me a Mac -“

“A Big Mac and a burger?” the driver asked.

“Yeah.” Mr. Weiner finished the list for the fifth time: “Fries, Coke.”

“I thought you just meant McDonald’s.” The kid changed lanes.

Mr. Weiner shook his head and unwrapped the cheeseburger. “Oh, this is delicious!” he exulted. “Mmmm. Oh my God, there is nothing quite as enticing as a two-hour-old cheeseburger at the end of a long day.”

He took another bite.

One of Mr. Weiner’s stock lines is that he’s always one step ahead, and that seems particularly pertinent when he’s sitting around kibitzing. He has a way of seeming hyper-focused and obsessed with whatever he’s talking about, but there’s no telling when he’ll tire of the subject at hand. His attention doesn’t wander as much as it flits about, as brilliant and elusive as a firefly on a sticky summer night.

On the ride up to the Bronx, Mr. Weiner’s aides hung onto his every word as he leaped from the British boycott of Israeli scholars to the Hybrid’s blinking dashboard to the lack of peanuts on the shuttle. The ride was made even more frantic by Mr. Weiner’s insistence that his driver pick up the speed as traffic came to a standstill, and missing the Riverdale event started to seem increasingly possible.

The congressman even started issuing orders to drivers other than his own. Coming off the George Washington Bridge, he yelled at a car in front of him, “Come on, it’s a yield, ya knucklehead, not a stop and think.”

Mr. Weiner has hockey scars around his eyes and a hatching of lines across his forehead, but he still looks younger than his 40 years. At 6 feet tall, Mr. Weiner appears to weigh about 100 pounds. In television interviews, he makes fun of his looks, prefacing statements with lines like “With a face like this …” – though in person, there seems to be no shortage of self-confidence.

Mr. Weiner shares with the City Council speaker, Gifford Miller, the distinction of being stuck at the bottom of the polls among the four Democratic mayoral candidates, with 13% or 14% of voters behind him, depending on which poll you go by.

And yet he’s come to be a cynosure of political insiders and papers like the New York Times. He’s also a hit with the New York Post’s Page Six: A Google search of “Anthony Weiner” and “Page Six” yields 76 hits, second only to Mr. Miller, and the council speaker can’t boast of a report that he was spotted “swapping spit” with a young woman at a bar in D.C.

In short, Mr. Weiner has got a lot going for him. He’s a clever Brooklyn boy. With a slight Alvy Singer accent, he talks about the “neighborhood shopping strip” and men on Wall Street in their “fancy suits,” appealing to the same middle-class outer-borough voters who put Ed Koch and Rudy Giuliani in office.

Another boon: He’s very funny. Talking to the board members of the League of Conservation Voters the other night about a park in Dumbo, the area down under the Manhattan Bridge, Mr. Weiner hesitated and asked his audience: “Can I call it that? You never know. Political correctness in campaigning does not come easily to me. Maybe you’re not supposed to say ‘Dumbo.’ “

“Weiner has ‘It’ like Schumer has ‘It,’ ” a professor of political science at Baruch College, Douglas Muzzio, said. “By ‘It’ I mean he’s staying at the bar until two in the morning, shaking hands with the last drunk, to get votes. He has a maniacal, Type A, obsessive personality. Mr. Obsessive as mayor – it could be fun.”

***

Only a few miles away from the school in Riverdale where Mr. Weiner was to give his first speech of the evening, the spaceship-like control board of the hybrid car died, and the Ford shut down in the middle of the road. Panicked, the mayoral candidate talked his driver through the process of restarting the car.

That happened again. By the third time, Mr. Weiner’s face was starting to sport a shiny veneer.

“This is the thing the League of Conservation Voters didn’t tell me about when they encouraged me to buy a hybrid car for my campaign,” he said with a sigh. “This is something to do with buying an experimental vehicle that took NASA to design. I have to send it actually to the NASA space center to be serviced.”

Within minutes, the car had managed to pull up outside the school. As the congressman strode into the building, a staff member who had arrived there beforehand called out: “You’ve got some angry Riverdalians inside.”

Mr. Weiner rushed to the front of the auditorium, whipped off his blazer, and started: “Just now my car – a brand-new hybrid Escape – broke down. This is what happens when you buy a car made by NASA – you’ve got to send it back to the Kennedy Space Center to be serviced.”

The joke earned him hearty applause, and the Riverdalians didn’t seem so angry. One disappointed man in the back of the auditorium mumbled, “Where’s Freddy Ferrer?” – the former Bronx borough president lives in the neighborhood – but most of the people responded well, chuckling and listening and diligently jotting down notes as the candidate delivered his standard three-pronged pitch. In short: 1) He’s for democracy and has had enough of Mayor Bloomberg’s top down style; 2) No more passivity in City Hall – he’s going to get more money for the city from the federal government; 3) He’s the ideas guy, and he’s figured out how to make the city work better. Mr. Weiner caps off his routine by saying, “If you want more of the same, you do not want to vote for me.”

***

Mr. Weiner got his start in politics when he was a skinny kid in Miss Noonan’s third-grade class at P.S. 39. Running for class vice president, he based his platform on the idea that the school cafeteria needed to stop serving fish sticks so often.

“I had a speech that I was going to give and I practiced it and I thought I did an excellent job,” the mayoral candidate recalled this month. His opponent – whose name he thinks was Eddie Rodriguez – wasn’t prepared to match wits with the future congressman. But the other kid did have a package of lollipops, which he handed out to the entire class. “I got creamed,” Mr. Weiner recalled.

The cornerstone of his mayoral campaign has been his big ideas – and the implication that his opponents haven’t thought things through as thoroughly as he has. Mr. Weiner has delivered eight in-depth policy speeches, covering such matters as health care and the city’s school system. His Web site boasts a downloadable book of 50 “Real Solutions” and mentions a neighborhood scrubbing-up program he started called “Weiner’s Cleaners.”

“A lot are things that have been bubbling in the cauldron of my mind for a long time,” he said.

That cauldron is not limited to political ideas. The morning of an interview with The New York Sun, Mr. Weiner stared at an Adam Sandler movie poster and wondered why so much of its real estate was wasted on credits. “Who reads the poster for that?” the congressman wondered. “Do they think that somebody walking down the street might be trying to hire a costume designer?” Mr. Weiner has yet to introduce legislation addressing that concern.

The great mystery of Mr. Weiner’s campaign is how the chattering classes can all be so keen on him and yet he still fares so poorly in the polls.

“This is always the way it is,” Mr. Weiner said. He tends to draw on his encyclopedic knowledge of New York political history when confronted with his own plight. “It’s how it was in Schumer’s race in ’88. I’m only trailing Virginia Fields 10 points. It’s a matter of getting the people to discover me. It’s going to happen,” he said.

It’s been bandied about that Mr. Weiner is merely using this race to make a name for himself for a future election, but he insists he’s in it for real.

“Particularly in politics,” he said, “people want to ascribe motives to everything, and they ignore the most obvious fact. I’d be a good mayor. That’s why I’m running. This is not something that you do cavalierly. I’m running harder – I would argue – than anyone else, including the mayor.”

***

Anthony David Weiner, whose district offices are in Sheepshead Bay, Rockaway, and Kew Gardens, grew up in Park Slope, a few houses down the block from Prospect Park. His mother, Fran, taught math at Midwood High School, and his father, Mort, was a neighborhood lawyer whose office had a shingle hanging outside. The Weiner parents split up as soon as the youngest of their three sons, Jason, now 37, left for college. The oldest son, Seth, died in a hit-and-run accident five years ago. Anthony Weiner prefers not to talk about it.

By Anthony’s lights, he was never much of a student, though Jason, who is now a restaurateur and chef in East Hampton, has another story to tell. “He’s always had a sense of humor, but he still had this serious, straight-arrow thing going on,” Jason Weiner said. “He was never in trouble. Seth was more of a free spirit. When I was in high school, I’d have a couple of drinks at parties. I don’t remember Anthony ever getting involved in any of that. He was kind of a tough act to follow.”

With both parents busy with careers, the boys would come up with their own means of keeping busy. When they were little, Anthony and Jason would play hockey in the bedroom they shared.

Mrs. Weiner was the intellectual introvert of the family. By nature, Mr. Weiner was more vocal, confrontational at times. The dinner hour chez Weiner was a bit like debate club practice, with politics and ideas dominating the conversation.

“At home, the discourse was always a little like Talmudic scholars dissecting,” Jason recalled. “There was a lot of ‘What do you think?’ Dad challenged us and made us defend our views.”

Anthony skipped seventh grade, and his parents were determined that he get into Stuyvesant High School. He came a point short on the entrance exam and was told he could attend only if he went to summer school, and so he sweated it out over the summer, working as a busboy and taking classes. “There was a lot of trigonometry,” he said. “And then the summer comes and goes, and I get a letter from the Board of Education saying, ‘We don’t want you.’ ” So off he went to Brooklyn Technical High School. During his high school years, he played hockey and ultimate Frisbee. He also grew out his hair and went through a bit of a “Rocky Horror Picture Show” phase.

As an undergraduate at SUNY Plattsburgh, he served on the student senate. He led a campaign to prohibit residential advisers from serving in student government, seeing as they were employees of the school.

A summer internship in the office of a Brooklyn congressman, Charles Schumer, turned into a six-year stint as one of his aides. At 27, Mr. Weiner was elected to the City Council, and at 34, he was elected to Congress.

Mr. Weiner has been linked with several women, including, at one time, a freelance television personality and “sometime dolphin cognition researcher” whose Web site features photographs of her in a barely-buttoned mechanic’s outfit.

He had always thought he would marry by age 30, but that didn’t pan out. He maintains that he wants to get married – and soon.

For now he’s shuttling back and forth between New York and D.C., where he shares a one-bedroom apartment with Rep. Michael Capuano, a Democrat of Massachusetts. The cats Mr. Weiner received as part of his settlement in a breakup, named Matisse and Chaka, live in his Forest Hills condo.

“I’ve kind of been married to my work for a while,” he said. “I’m ready to take a mistress.”

To hear his brother Jason tell it, Anthony isn’t always in go-go-go politician mode. “He turns it off and on,” the younger Mr. Weiner said. “At Passover, that’s not who he is.”

When Anthony visits Jason in East Hampton, he brings the past 30 New York Times Book Review sections, sits out on the beach, and reads them all day long. He doesn’t make it out there all that often.

Anthony Weiner said he’s never gone to therapy, and he’s tried yoga only once. “I went on Amazon and got a yoga DVD,” he said. “It lasted for 10 minutes. They were talking too calmly and quietly. It wasn’t my speed.”

***

After the Riverdale speech was over, a car – this time an old-fashioned, air-polluting one – was outside the school waiting for Mr. Weiner. A different aide was behind the wheel. As the car sped down the West Side Highway, cell phones clicked open and shut as the Weiner team tried to gauge whether it was too late to speak to a Brooklyn political club before members cast their votes on a mayoral endorsement.

Mr. Weiner rolled down his window to let in the night air, but it didn’t do much to dent the tension. Aides said things like “Did they vote yet?” and “How many bodies are left?” into their cell phones.

Following Mr. Weiner’s insane directions, the driver made it from the Bronx to Brooklyn in good time, but it was still too late. The votes had already been cast. The winner: Gifford Miller.

Undeterred, Mr. Weiner shot to the front of the room and delivered his spiel.

“Well, I knew I wasn’t going to win that club,” he said afterward, as he slowly walked toward the car. “But I wanted to make them feel a little guilty about voting for someone else.”