 -- Just 24 hours after being charged with assault for allegedly body-slamming a reporter in his Bozeman campaign office, Republican Greg Gianforte on Thursday defeated Democratic opponent Rob Quist to win the special election for the U.S. House seat in Montana.

The race was thrust into the national spotlight in dramatic fashion on Wednesday night after Guardian reporter Ben Jacobs described being "body-slammed" by the GOP candidate, and a Fox News crew who witnessed the incident said the former technology and software executive "grabbed Jacobs by the neck with both hands and slammed him into the ground behind him."

"I'm sick and tired of you guys," Gianforte said in audio of the event released by The Guardian. Jacobs told "Good Morning America" Thursday morning, "I went from being vertical one moment to being horizontal the next."

After the incident, the Gallatin County Sheriff cited Gianforte for misdemeanor assault, and instructed him to appear in court by June 7.

Democrat Quist had hoped to turn the broad unpopularity of President Donald Trump into a win for national Democrats at the ballot box.

Trump won the state by more than 20 percentage points in November's election, though the state re-elected its incumbent Democratic Gov. Steve Bullock by a narrow margin on the same day.

The U.S. House seat became vacant after Trump tapped Republican Congressman Ryan Zinke to become Secretary of the Interior.

Nearly 70 percent of votes in Montana were cast early -- before the alleged assault took place. According to the Associated Press, with 95 percent of precincts reporting, Gianforte led 51 percent to Quist's 43 percent.

Speaking to supporters in Bozeman late Thursday night after his win had been called, Gianforte apologized for his actions on Wednesday.

"When you make a mistake you have to own up to it, that's the Montana way," Gianforte said. "Last night I made a mistake... That's not the person I am and it's not the way I'll lead in this state."

"Rest assured, our work is just beginning, but it does begin with me taking responsibility for my own actions," he added. "You deserve a congressman who stays out of the limelight and just gets the job done."

Gianforte's apology contradicts the statement his campaign released Wednesday evening blaming the incident on "aggressive behavior from a liberal journalist."

Republican National Committee Chairwoman Ronna McDaniel released a statement following Gianforte's victory approving of his decision to apologize.

"Congressman-elect Greg Gianforte was right to apologize for his actions in Wednesday’s incident," McDaniel said. "Tonight’s apology was a good first step toward redemption and I hope Gianforte continues to work toward righting his wrong.”

The day after the alleged assault, House Speaker Paul Ryan condemned Gianforte's behavior and called for him to apologize, but didn't say he should withdraw from the race.

"There is no time where a physical altercation should occur with the press or just between human beings," he told reporters. "So, that is wrong and it should not have happened."

Three Montana newspapers who had previously endorsed the candidate withdrew their endorsement on Wednesday night, but President Donald Trump, who had endorsed Gianforte via a robocall, did not have a comment Thursday on the alleged assault.

Gianforte has been supportive of Trump's travel ban and health care reform, and backed the president's decision to fire former FBI Director James Comey.

Before running for the congressional seat, Gianforte unsuccessfully ran for Governor of Montana in 2016. Before that, he was a technology and software company executive -- his assets range between $96 and $328 million, according to the Associated Press.

Thursday's election leaves Democrats without a win in special elections since November, with Republicans having won contests in Louisiana, Kansas and now Montana. But they'll have more chances next month, as candidates battle for House seats in three special elections in California, Georgia and South Carolina.