NEWARK — They first met in 2002: Cory A. Booker, then an upstart councilman trying to topple this city’s political machine, asked Chris Christie, New Jersey's chief federal prosecutor, to monitor the election for intimidation and voter fraud.

When Mr. Booker became Newark’s mayor in 2006, they found common ground as political outsiders promising to fight crime and corruption in a city plagued by both. When Mr. Christie was elected governor last fall, one of the first things he did was join the mayor for a late-night ride with police officers through some of New Jersey’s most dangerous streets.

This year, Mr. Christie, the blunt-speaking suburban white Republican, and Mr. Booker, the Scripture-quoting urban black Democrat long rumored to want the governor’s job, have become the state’s political odd couple. They talk or text each other perhaps a dozen times a week, and go out of their way to praise each other publicly. The two men went to a Giants game together a few weeks ago and have bonded over their mutual devotion to New Jersey’s bard (the governor has been to more than 100 Bruce Springsteen concerts, and the mayor often tweets the Boss’s lyrics).

“I’ve told him when Bruce comes back, I’m taking him,” Mr. Christie said Thursday.

Last week’s announcement regarding a planned overhaul of Newark’s schools vaulted their surprising partnership to new levels of significance and visibility, potentially binding the two men’s political futures, with opportunities and risks for both. After 15 years of state control of Newark’s troubled public schools, the governor put the mayor in charge of revamping the system, and together they announced a $100 million gift to the schools from Mark Zuckerberg, the Facebook chief executive, on the “Oprah Winfrey Show.”

Their styles could hardly be more different — the direct, pugnacious Mr. Christie barreling through opposition, the eloquent Mr. Booker seeking consensus. That contrast was on display here Saturday, in one of a series of appearances with Mr. Zuckerberg, when they were asked if the teachers’ union might resist school reform. Irritation flashed across Mr. Christie’s face and he traded a few whispered words with his other half.

“The governor said, ‘Either you step up to the microphone or I’m going to grab it and go off,’ ” said Mr. Booker. “And he probably will, anyway.”

Sure enough, after the mayor spoke of moral and educational uplift, of shared vision and sacrifice, warning gently that “there’s no safe way to have school reform,” the governor unloaded. “Frankly, I don’t give a damn what they think,” Mr. Christie said, calling the teacher’s union “destructive to our educational system,” among many other unflattering things.

By all accounts, Mr. Booker, 41, and Mr. Christie, 48, each of whom are often talked about as rising national stars in their respective political camps, get along well.

“The part you can never discount is I like him, and that makes it much easier” to work together amid disagreements, Mr. Christie explained. “I think he’s in the business for the right reasons.”

Compared to the evasive dodges practiced by so many politicians, Mr. Booker said, “It’s refreshing to sit down with a guy who, in response to your ideas, says ‘yes,’ ‘no,’ ‘yes,’ ‘yes,’ ‘hell no.’ ”

The two men long ago decided that there were three areas they could agree enough to work together: crime, redevelopment and education. Indeed, after winning the governorship in November, Mr. Christie’s first public appearance was not with fellow Republicans, but with Mr. Booker at a Newark charter school.

Mr. Booker is one of a handful of black Democrats who have long advocated private school vouchers for poor students in failing schools and the expansion of charter schools — positions more common among Republicans. He has also supported principles dear to Mr. Christie that are often resisted by Democrats’ allies in organized labor, like setting performance standards for teachers and administrators.

This year, the mayor also backed the governor’s plan to cap local property tax increases, an endorsement that Mr. Christie trumpeted during his successful push to get the idea put into law.

“Many people would pigeonhole Booker, assuming that he fits a certain liberal profile, but his politics are much more complex than that,” said Brigid Harrison, a political scientist at Montclair State University. Mr. Booker and Mr. Christie both want to address Newark’s ills, she said, “and they know they need each other to do that.”

Both men rose to power largely outside the state’s entrenched, often corrupt political machinery — each first ran for office against an incumbent from his own party — and aides say they share a disdain for that establishment. They certainly share an enmity for Sharpe James, the longtime Newark mayor who narrowly defeated Mr. Booker in 2002 — and who was among the more than 100 government officials that Mr. Christie successfully prosecuted during seven years as United States attorney.

They disagree on plenty of things but keep those disputes muted, at least in public. During last year’s campaign against Gov. Jon S. Corzine, a Democrat, Mr. Booker recalled Mr. Christie saying to him, “I understand you have to support Governor Corzine, but I have to ask one thing from you: Don’t lie about me.”

This year, Mr. Booker supported bills in Trenton to allow gay marriage and impose a “millionaire’s tax,” both measures that were opposed by Mr. Christie (and were defeated). The mayor quietly opposed the governor’s budget cuts to his city and its school district — so quietly that he drew fire from some of the people fighting those cuts.

“Other Democrats would have liked him to join in the hue and cry, but that’s not Booker’s style,” said Ingrid W. Reed, New Jersey Project director at the Eagleton Institute of Politics at Rutgers University. “He’s always trying to strike a reasonable tone, so he can say, ‘Look, I don’t like it, but the state doesn’t have the money.’ ”

In New Jersey, the political center of gravity rests with moderate voters leery of both major parties. The alliance could help both men appeal to that vast middle. But it could also hurt them politically, if there is a public falling-out over how to manage and pay for education, or if Newark’s schools fail to improve. For years, Mr. Booker, who was easily re-elected in May, said he could not imagine serving more than two four-year terms as mayor. The buzz in political circles was that he might run for governor in 2013, putting him on a collision course with his new companion.

“We’ve talked about it,” Mr. Christie said. “I never asked him for any promises or guarantees about what he’s going to do in the future."

But such a challenge suddenly became harder to picture as the two sat side by side on national television and in community events last week. And in the last few days, Mr. Booker has said he might just stay put for a third term, after all, to carry out his education plans.

Intended or not, for Mr. Christie, that might be the biggest political coup of all.