When he was 37, Booker replaced James as mayor, and his national stature soared.
Now 44, he is the favorite to win the New Jersey Senate seat recently held by the late Sen. Frank R. Lautenberg. He would become the chamber's seventh-youngest member and the ninth African American U.S. senator, the fourth popularly elected.
Friends, usually unprompted, predict that he will quickly become a leading national voice and a future presidential contender.
"Where he wants to be down the road, this is the right place at the right time," said one ally, Essex County Executive Joseph DiVincenzo.
Such chatter has long followed Booker, and he has done little to tamp it down. When Booker was still a councilman in 2002, former Gov. Brendan T. Byrne predicted in the New York Times that he would become president.
At every step, Booker has charted his own route and muscled his way past the establishment.
With a huge advantage in money and popularity, he's now in position to surge past three Democratic stalwarts, U.S. Reps. Frank Pallone and Rush Holt and New Jersey Assembly Speaker Sheila Oliver, in Tuesday's primary.
If he wins, Booker will be favored against either Republican contender, conservative leader Steve Lonegan or physician Alieta Eck.
And despite being mayor of a midsize city of about 275,000, he would enter the Senate with a bigger name than most of his colleagues.
As he runs, though, Booker has couched his ambition in terms of helping others.
"We all should have high expectations and aspirations to make a difference," he said. "That's what my parents wanted for my brother and I in our early years, so we could contribute to the evolving story in America."
Booker recently told reporters that he has "absolutely" and "unequivocally" ruled out running for president or vice president in 2016.
But hours before those comments, he was less definitive when asked more broadly about a presidential bid, not specifically about 2016.
"I don't know where my future leads," he said in an interview. "To me, what's important is not ascending to an office; it's using all the gifts that I have, or the opportunity that I have, to try to make a difference."
Pressed, he said: "We really make a mistake when we lose our focus on the task right before us and begin to look at the task down the road."
Booker said he entered public life because his parents saw firsthand how policy could impact lives.
His father was born to a poor, single mother "in the mountains of North Carolina." But Booker said the civil-rights movement opened opportunities his parents might have once been denied. His father was one of IBM's first black executives and raised his sons in a place where he once would have been excluded, Harrington Park, an affluent Bergen County suburb.
"My parents made it very clear to me that I would not be where I was today if it wasn't for these uncommon coalitions that came together to produce uncommon results," Booker said.
Campaigning for Senate, Booker vows to build new coalitions to mend the fractious politics in Washington. A gifted speaker with a knack for grabbing headlines - once rescuing a neighbor from a fire - he holds largely liberal views, though he is more moderate than his Democratic opponents.
Booker has worked with Gov. Christie, backing the Republican's big initiatives on pension and teacher reform, supported school vouchers - an idea that is anathema to many liberals - and at times vocally defended Wall Street banks, even from attacks by President Obama in the 2012 presidential race.
His broad appeal is why Booker on one recent day could tour a senior citizens' home in the afternoon and host a fund-raiser with Oprah Winfrey that night, skipping an NAACP candidates' forum in Newark for the event with the media empress.
It's why the black and Baptist Booker could become a founding member of the Jewish Chai Society at Yale. He can drop Yiddish or Spanish into his speech, depending on the crowd.
To a Twitter following of 1.4 million, he talks up his love of ice cream, Star Trek: The Next Generation, and Buffy the Vampire Slayer. At other times he sounds like a businessman, saying Congress needs more "innovation and entrepreneurialism."
Booker says his record in Newark is the biggest reason for his support. He points to a drop in most violent crimes and a building boom in the long-beleaguered city, though poverty and unemployment remain widespread and critics charge that he has focused more on fame than the city.
The Lautenberg family has called him a "show horse."
Booker points to his work. Fresh from Yale Law, he moved into Brick Towers, a notorious housing project.
"I wanted to be part of a community that was struggling to make true on the promise of America," he said in his typically sweeping way.
On a recent rainy day in North Jersey, he arrived late to a campaign stop at a nursing home, all energy. Staffers in scrubs held camera phones aloft.
When Linda Wilson, 66, raised her hand to speak, she told Booker she was blind.
"I'm here," Booker said, and sat by her so she could feel his presence. "I'm going to hold your hand while you ask a question."
A former Democratic legislative aide, Wilson spoke about the need to overhaul nursing homes to care for a wider range of ages. Booker listened intently, his hand resting between hers.
"He's the perfect man for the job," Wilson said later. "He's new blood, he's definitely innovative, and he's a people person."
Later, Booker would rally with Winfrey, but first he told the seniors a joke that he said would be terrible.
"What do you call 100 rabbits in a line moving backward?" the bald mayor asked.
"A receding hare line."
It was as bad as advertised. His audience laughed anyway.
Cory A. Booker
Education: B.A. in political science and M.A. in sociology at Stanford University; B.A. as a Rhodes scholar at Queen's College, Oxford; J.D. from Yale
Experience: Newark City Council, 1998-2002; attorney, Trenk DiPasquale, 2002-06; Newark mayor, 2006-present.
Family: Single, no children
Key Causes: Help poor cities recover; foster cooperation in Washington
Contact Jonathan Tamari at email@example.com or follow on Twitter @JonathanTamari. Read his blog "Capitol Inq" at www.inquirer.com/CapitolInq.