SALEM — Seth Moulton, a Harvard Business School graduate and Marine veteran, on Tuesday became the first Massachusetts Democrat in 22 years to oust a sitting congressman from his own party, decisively defeating embattled nine-term Representative John F. Tierney and setting the stage for an unpredictable general election in November.
Tierney, the veteran North Shore congressman, has been politically vulnerable since 2010 when his wife, Patrice, was convicted on federal tax charges in connection with her brothers’ illegal offshore betting operation. But after twice prevailing against Republican challengers, he was felled in Tuesday’s primary by a fellow Democrat who appealed to voters’ frustration with intransigence in Washington and made a compelling case for change.
“Our win tonight says two things,” Moulton told the crowd at his victory party at the Veterans of Foreign Wars post in Salem. “First, that we are fed up with the gridlock in Washington. And second, that voters want to keep this seat blue.”
Moulton will face Republican Richard Tisei, the former state Senate minority leader who nearly toppled Tierney two years ago, in the November election. Moulton’s win complicates the race for Tisei, who had been considered well positioned to unseat Tierney.
The Republican, who faced no primary challenger, betrayed little concern about the Democratic results in an interview.
“The winds of change are blowing through this district,” Tisei said.
Previewing how the race is likely to unfold, Tisei said Moulton represents more of the same.
“Seth pretty much said he would vote the exact same way John Tierney voted,” Tisei said. “That’s not the change people want in terms of changing the direction of the country. I look forward to having a spirited debate about where we go from here.”
“I just think we need to get new blood in there,” said 86-year-old Elizabeth O’Connor, a Lynn Democrat who voted in the basement of St. Pius V Catholic Church. “I thought it’s time to give somebody younger a chance.”
The exuberant crowd packing the VFW hall waved small American flags as Moulton entered, trading hugs and high-fives with their candidate and asking him to pose for photos.
“We won! We won!” Kim Phifer shouted.
Moulton, 35, appealed to voters with an unusual biography: Raised in Marblehead by antiwar liberals, he went on to become a Marine captain who served four tours in Iraq after graduating from Harvard College with a degree in physics.
Moulton also earned degrees from Harvard’s Kennedy School of Government and business school.
His list of high-profile supporters include former presidential adviser David Gergen and retired generals David H. Petraeus and Stanley McChrystal, who helped him raise $1.6 million during his first campaign.
For the most part, he did not dredge up the family controversy that has dogged the Tierneys. Instead, he criticized the congressman for his record in office, airing a TV ad that blasted Tierney for having passed just one bill in 18 years in Washington.
Tierney fired back last week, with a negative ad that seemed to indicate his campaign was more concerned about the primary than his advisers had previously let on.
Tierney, 62, enlisted the backing of party leaders including Senator Elizabeth Warren and House minority leader Nancy Pelosi, who in recent weeks lent their heft to advertising, fund-raising, and get-out-the-vote efforts aimed at igniting the Democratic base.
Tierney issued a brief concession speech shortly before 9:30 p.m., thanking his family, particularly his wife, for their love and support.
“I’m proud of the work that we’ve done in Congress,” Tierney said. “This was just an amazing 18 years.”
In his victory speech, Moulton thanked Tierney for his service, calling him “a true advocate for progressive values and civil rights in Washington.”
Moulton did not exempt Democrats from blame in Washington, telling his supporters that it’s “not enough to blame Republicans for the lack of progress at a time when our country faces so many challenges.”
The last time a Democratic incumbent was turned out of office by a member of his own party was 1992, when Martin T. Meehan beat out Representative Chester Atkins in the party primary after Atkins became ensnared in a banking scandal.
It has been 18 years since any congressional incumbent in Massachusetts was voted out of office in a general election. In 1996, it was Tierney himself who in the general election ousted Republican Representative Peter Torkildsen.
That same year, James P. McGovern defeated Republican Representative Peter Blute.
The Sixth Congressional District extends from the New Hampshire border south to Bedford and Lynn and east to Rockport. In winning, Moulton also defeated three other Democrats, Middleton immigration attorney Marisa DeFranco, John P. Devine, and John J. Gutta.
Tisei noted that Massachusetts Democrats are in the minority in the House and have relatively little tenure, compared with past years. With the turnover in the North Shore congressional seat, seven of the 11 members of the Massachusetts congressional delegation will have taken office since 2007.
“I think I can be a more effective change agent as a member of the majority party who can deliver for the district and the state,” Tisei argued, pointing to his 26 years of experience in the Massachusetts Legislature.
As Tierney supporters absorbed the loss, one credited Moulton for running a smart campaign while praising Tierney’s 18 years in Congress.
“The Sixth Congressional District deserves the best,” said Tierney backer Marsha Finkelstein, chairwoman of the Salem Democratic City Committee, sipping a glass of red wine. “We had the best in John Tierney. It’s going to be big shoes to fill.”
Matt Viser of the Globe staff contributed to this report. Stephanie Ebbert can be reached at Stephanie.Ebbertemail@example.com. Follow her on Twitter @StephanieEbbert. Kathy McCabe can be reached at katherine.mccabe@
globe.com. Follow her on Twitter @GlobeKMcCabe.