The decisive victory of Luke Bronin, a Yale-educated lawyer and former Obama administration official, in Hartford’s Democratic mayoral primary Wednesday was driven by the newcomer’s prodigious fundraising network and a struggling city’s hunger for change.

Unofficial results gave Bronin, 36, a first-time candidate backed by a coalition of white and black voters, a comfortable nine-percentage-point win over Mayor Pedro Segarra, a margin unlikely to encourage the incumbent to continue as an independent in November.

In the state’s largest city of Bridgeport, there was no such clarity after Joe Ganim, the former mayor and felon, claimed victory over Mayor Bill Finch in a close three-way primary. Finch promised to continue in November on a third-party line.

Democrats also denied endorsement for another term to New London Mayor Darryl Finizio, who lost to Councilman Michael Passero.

Bronin, a Rhodes scholar with a network that reaches from the Greenwich Country Day School of his youth to his more recent association with political activists in some of the poorest urban precincts in the U.S., now faces the daunting task of delivering a new day.

“When you have a big victory, the expectations are high,” said Shawn Wooden, the outgoing City Council leader, one of a long list of politicians who lined up behind Bronin over the summer. “Luke Bronin, I believe, is someone up to the task.”

Bronin claimed victory shortly after 10 p.m. in the crowded auditorium of the Polish National Home, mindful of those expectations.

“We did it!” he shouted.

But Bronin quickly pivoted, noting that the city’s challenges, including “Depression-era unemployment,” low-performing schools and street violence were years in the making. Solutions will not come quickly, he said.

Rep. Douglas McCrory, D-Hartford, an educator who represents a black district, said Bronin and his entire slate won with unexpectedly broad support. Treasurer Adam Cloud, who also won, was the only incumbent to run with Bronin.

“We’re starting with a new slate,” McCrory said. “It’s a fresh start.”

“We’re at a crossroads,” said Dr. Robert Painter, a former council member. “We’ve been dribbling along, getting by, but without much inspiration.”

Bronin moved to Hartford in 2006, but he was absent from the city while serving in Afghanistan with the U.S. Navy and then working during President Obama’s first term as a lawyer assigned to tracking terrorist financing.

Segarra, a lawyer and former social worker, was the council president who automatically succeeded Mayor Eddie A. Perez, who resigned in the face of a corruption scandal in 2010. He was elected to a four-year term in 2011.

“Your continued support means so much to me, and I feel so fortunate to be here with you all tonight,” Segarra told his supporters. “While I am disappointed in tonight’s results, this does not change my commitment to this campaign nor the people of Hartford.”

But Segarra, who originally had pledged to run as an independent in November if he lost, hedged on going forward, as he did in a brief interview Tuesday. Segarra, who has struggled to raise money, said he would reflect on the results before deciding whether to continue.

Bronin urged his supporters to think about unity.

“We are one city, one small city,” he said. “It’s time for each of us to reach across to someone who was on the other side of the primary.”

Among the congratulatory calls was one from a former boss, Gov. Dannel P. Malloy. Bronin was the governor’s general counsel for two years before declaring his candidacy in January.

Malloy, who endorsed Finch, left no doubt this week he dreaded the prospect of a return to power by Ganim, who served seven years in prison stemming from bribes and kickbacks he accepted as mayor.

“I’d prefer not to cross that bridge,” Malloy said, when asked if he could work with Ganim.

Finch, a former state senator seeking his third term, was challenged by Ganim and Mary-Jane Foster, a businesswoman running for the second time. Foster ran a distant third Wednesday night.

In an interview on WTNH, Ganim was focused on what lay ahead.

“Every door we knocked on, people wanted to talk about the future,” Ganim said, adding voters were interested is addressing the city’s crime and education problems. “I’ve been there, and I have some experience.”