HELENA, Mont. — Steve Daines won a U.S. Senate seat on Tuesday that Montana Republicans have not held in more than a century by defeating Amanda Curtis, a late substitution by the Democrats after Sen. John Walsh dropped out of the race.

Daines celebrated with family and supporters in his hometown of Bozeman as the Republican Party won control of the Senate by picking up Montana and five other seats.

“Tonight is not about the end of a campaign. Tonight is a beginning. It is time to get the United States Senate working for the people of Montana and working for America again,” Daines told the cheering crowd.

The last Republican to hold the seat was Joseph M. Dixon in 1913. Since then, the seat was held by Democrats. For 35 years, it was occupied by Max Baucus, who announced last year he would not seek a sixth term and then resigned in February to become ambassador to China.

Daines, 52, launched his Senate bid less than a year after winning his first election to the U.S. House in 2012. He had spent 27 years before that in the private sector, first as a manager for Procter and Gamble and later as an executive with the Bozeman-based RightNow Technologies.

Daines’ voting record in Congress pegged him as the most conservative representative from Montana since World War II, according to an analysis by Montana State University professor David Parker. 

Daines said he is confident that he and Montana’s senior senator, Democrat Jon Tester, will be able to work together on legislation important to residents of the state.

“There is a long list of problems to be solved,” he said.

The Democrats struggled to find a candidate to replace Baucus once he announced he wouldn’t run again. Their top choice, popular former Gov. Brian Schweitzer, said no, followed by a slate of other potential candidates. Finally, Walsh stepped up and announced his candidacy in October 2013. 

Walsh was a career National Guardsman and the state’s adjutant general, and his only other run for political office had been as Gov. Steve Bullock’s lieutenant governor in 2012.  Walsh’s campaign received a huge boost in February, when Bullock appointed his lieutenant governor to fill the rest of Baucus’ term when Baucus resigned early to become ambassador to China. 

Then in July, The New York Times published a story that revealed Walsh had plagiarized large portions of a research paper required for his master’s degree from the U.S. Army War College in 2007. 

He and his campaign tried to move on from the allegations, but couldn’t. Walsh announced in August he was dropping out of the race because the issue had become too much of a distraction for him to effectively campaign. 

Delegates to a special Democratic party nominating convention chose Curtis, a one-term state legislator and high-school math teacher from Butte, to replace Walsh as the Democrats’ nominee. 

Curtis, 35, took a three-month leave of absence from her job and scrambled to assemble a campaign and raise money to challenge Daines. Time was against her, but she debated Daines twice and managed to raise nearly $1 million for her run.  

Curtis declined to comment, but her campaign released a statement from her congratulating Daines.

“It is my sincere hope, and the hope of all Montanans, that he reaches out to working families to better understand the issues that affect us,” she said.

Roger Roots also ran as the Libertarian candidate.