A pro-Israel centrist, George Latimer, defeated Congressman Jamaal Bowman on Tuesday in a Democratic primary at suburban New York that highlighted the party’s deep divisions over the war in Gaza.

With the victory, Mr. Latimer has ousted one of the most liberal voices in Congress and one of its most outspoken critics of Israel. Mr. Bowman has accused Israel of committing genocide in Gaza, where thousands of Palestinians have died in military strikes.

Mr. Latimer, who got into the race at the urging of Jewish leaders and had substantial financial backing from the American Israel Public Affairs Committee, is a former state legislator who has served as Westchester County executive since 2018.

In a victory speech, Mr. Latimer called for more civility following the contentious election.

“We have to fight to make sure we don’t vilify each other and we remember that we’re all Americans, and our common future is bound together,” he told supporters at an event at White Plains.

“We argue, we debate, we find a way to come together,” he said, adding that all representatives had a duty to find ways to work across political divides and prevent the country from splintering.

Mr. Bowman had been seeking a third term, representing a district in New York City’s northern suburbs. His defeat is a blow to the party’s progressive wing and a potential cautionary tale for candidates trying to shape their messaging around the Israel-Hamas conflict.

His loss also disrupted what has generally been a stable primary season for congressional incumbents. Most current members of Congress have been able to repel challenges from within their party, though Congressman Bob Good is in a tight contest with a rival backed by President Trump in a race that is too close to call.

“This movement has always been about justice. It has always been about humanity. It has always been about equality,” Mr. Bowman said at his election party at Yonkers, conceding that he lost the race but remaining unapologetic about his opposition to the war in Gaza.

The American Israel Public Affairs Committee’s political action committee spent nearly $15 million on the primary, filling airwaves and mailboxes with negative ads in an effort to unseat Mr. Bowman, who has accused the influential pro-Israel lobbying group of trying to buy the race.

“The outcome in this race once again shows that the pro-Israel position is both good policy and good politics — for both parties,” the American Israel Public Affairs Committee said in a statement.

Some major progressive figures have rushed to Mr. Bowman’s defense. In the final stretch of the race, he rallied with Congresswoman Alexandria Ocasio-Cortez and Senator Sanders, while Mr. Latimer pulled in the endorsement of the former presidential candidate and Secretary of State, Hillary Clinton.

On Israel, both Mr. Bowman and Mr. Latimer support a two-state solution. They have also both condemned Hamas’ October 7 attack on southern Israel that killed around 1,200 people.

Mr. Bowman was one of a few progressives who rejected a symbolic House resolution in support of Israel following the October 7 attack. Mr. Latimer firmly backs Israel and said negotiating a cease-fire with Hamas is a non-starter because he believes it is a terrorist group.

Mr. Bowman was first elected in 2020 after running as a liberal insurgent against a moderate congressman, Eliot Engel, a 16-term congressman who chaired a House committee on foreign affairs. Mr. Bowman, 48, embraced the political outsider strategy this year as well, depicting Mr. Latimer as a tool of Republican donors and pro-Israel groups.

Mr. Latimer said Mr. Bowman’s criticism of Israel was only part of the reason why he decided to challenge the incumbent. He said Mr. Bowman hasn’t been attentive to the needs of the district, maintained few relationships with its leaders, and was more interested in getting spots on cable news than he was in helping people.

During the campaign, Mr. Latimer, who has more than three decades of political experience, often displayed his deep regional knowledge and connections to make the case that he would be an effective member of Congress.

Mr. Latimer has said that’s the sort of politics people expect from their elected officials, rather than caustic fights between the far right and far left — a clear dig at Mr. Bowman.

Aside from his position on Israel, Mr. Bowman has been followed by lingering criticism over an incident last year when he triggered a fire alarm in a House building while lawmakers were working on a funding bill.

He said it was unintentional, with the alarm going off when he tried to open a locked door while trying to vote. Mr. Bowman was censured by his colleagues in the House, and the incident drew embarrassing news coverage.

The congressional district’s boundaries have shifted since Mr. Bowman first won office in 2020, losing most of its sections at the Bronx and adding more of Westchester County’s suburbs.

Today, 21 percent of its voting-age population is Black and 42 percent is non-Hispanic white, according to U.S. Census figures, compared to 30 percent Black and 34 percent white in the district as it existed through 2022. Mr. Bowman is Black. Mr. Latimer is white.

Mr. Bowman, as the election neared, focused on driving up turnout at what parts of the Bronx remain in his district, telling supporters there that the contest could hinge on their votes.

He spent the bulk of his election day at the Bronx, too, and a video posted to the social media site X showed Mr. Bowman walking down a street at the Bronx with a drum line behind him on Tuesday.

Mr. Latimer, 70, will be the prohibitive favorite to win in the general election. The district, which includes parts of Westchester and a small piece of the Bronx, is a Democratic stronghold.

Nationally, Democratic Party leaders have emphasized moving toward centrist candidates who might fare better in suburban races.

Also on Tuesday, Democratic voters on Long Island picked former CNN anchor John Avlon as the candidate who will challenge the incumbent, Congressman Nick LaLota, at a district that’s been controlled by the GOP for a decade.

Mr. Avlon defeated retired chemistry professor Nancy Goroff in the Democratic primary. The Long Island congressional district has become a priority for Democrats as the party tries to flip suburban seats in New York as part of a strategy to win a House majority.

Only winning the seat could be an uphill battle for Democrats in November, after Democratic state lawmakers changed its borders during redistricting to make it slightly more friendly to Republicans to improve their chances in other districts.

In central New York, Democrats picked a state senator, John Mannion, as the party’s nominee to take on a Republican who represents a recently reconfigured congressional district where President Biden beat Trump by 11 points in the 2020 election, Congressman Brandon Williams. Mr. Mannion defeated a town councilor at the Syracuse suburb of Dewitt, Sarah Klee Hood.

In another race, the incumbent representative, Claudia Tenney, thwarted a primary challenge from an attorney and businessman, Mario Fratto, who had previously lost to Ms. Tenney in the last primary election for the safely Republican seat located along Lake Ontario.