UPDATED: June 26, 2013, at 1:09 a.m.

BOSTON—Edward J. Markey, a Malden Democrat and 37-year veteran of the House of Representatives, became the nation’s newest Senator-elect Tuesday night, riding a wave of party support to defeat Republican challenger Gabriel E. Gomez in a special election to fill the seat vacated earlier this year by Secretary of State John F. Kerry.

“This election is about your hopes, your dreams, your families, your future. And I know that,” Markey told a crowd of his supporters gathered at the Boston Park Plaza Hotel in Back Bay after the race was called.

Earlier in the evening, when returns showed that Markey had gained the advantage in votes counted, a cheer erupted among Markey supporters in the hotel’s ballroom. As Markey’s lead expanded, the atmosphere grew more and more celebratory. The Associated Press called the election for Markey shortly before 9:15 p.m., and final vote tallies late Tuesday night showed a 10-point victory for Markey, 55 percent to 45 percent.

In a race which drew little attention even within the Commonwealth, Markey boasted a vast field operation. According to campaign spokesperson Andrew Zucker, 7,200 volunteers made about one million voter contact attempts on Tuesday alone. In the four days before the vote, Zucker said, 15,000 volunteers made three million voter contact attempts. All told, 19,000 volunteers worked for the Markey campaign, according to Zucker.

Markey also received help from party leadership. Perhaps the three most recognizable Democrats in the nation—President Barack Obama, First Lady Michelle Obama, and Vice President Joe Biden—each made a trip to the Commonwealth to stump for Markey, as did former president Bill Clinton.

“When you get major figures like Obama and Bill Clinton and Joe Biden coming into the state, that tells Massachusetts voters that this is a nationally important contest,” Dan Payne, a Democratic political consultant who has done work for Markey, said in a phone interview after the race was called.

Gomez, on the other hand, struggled to generate the energy and enthusiasm that propelled Republican then-state senator Scott P. Brown to a surprise victory over his Democratic opponent, Massachusetts Attorney General Martha Coakley, in a 2010 special Senate election. While, like Brown, Gomez cruised to an easy victory in the Republican primary, by many accounts he lacked Brown’s charm and engagement on the campaign trail and observers said his performance in televised debates against Markey was up and down.

Some have suggested that Gomez was further hurt by a case of election fatigue in Massachusetts, where voters have been called to the ballot box four times in the past four years for special elections to fill open Senate seats.

On Monday, Massachusetts Secretary of State William F. Galvin, the state’s chief election official, predicted a record-low turnout of just 1.6 million voters, or about 37 percent of the Massachusetts electorate. Conversely, in the 2010 special Senate election, more than half of the electorate went to the polls, in part representing a surge of independent voters who supported Brown. As of Tuesday night, Galvin’s estimate appeared ambitious; with all precincts reporting, only about 1.17 million ballots had been tallied.

—Staff writer Matthew Q. Clarida can be reached at clarida@college.harvard.edu. Follow him on Twitter @MattClarida.