Mike Collins beats the Trump-backed Vernon Jones in the G.O.P. runoff for a House seat in Georgia.

ATLANTA — Mike Collins, the owner of a trucking company, easily won the Republican runoff election on Tuesday for Georgia’s 10th Congressional District, knocking out Vernon Jones, a former state lawmaker and Democrat-turned-Republican who had the backing of former President Donald J. Trump.

Mr. Collins’s victory was called by The Associated Press. If he wins the general election in November, he will represent a solidly conservative district that stretches from suburban Atlanta to Augusta.

Mr. Collins benefited from name recognition within the district — he ran for the seat in 2014 and narrowly lost to Jody Hice — and higher fund-raising than the rest of the primary field. He received an endorsement from Gov. Brian Kemp in the final week of the runoff campaign, marking the governor’s first and only endorsement in a primary.

Mr. Jones initially jumped into the Republican primary for governor, challenging Mr. Kemp. But Mr. Trump persuaded him to switch to the House race in an effort to clear the field for his preferred candidate, former Senator David Perdue, who lost last month. Mr. Jones, a former DeKalb County executive, struggled to raise money and earn the trust of some voters in light of his past in Democratic politics. He also faced accusations of misconduct toward women, which he denied.

But he leaned into his endorsement from Mr. Trump, fashioning himself as a Black conservative in the former president’s mold. In fiery speeches and public statements, Mr. Jones repeatedly lobbed insults at both Mr. Kemp and prominent Democrats while echoing Mr. Trump’s false claims of election fraud.

The runoff campaign between Mr. Jones and Mr. Collins turned personal in its final weeks. Mr. Collins, whose father represented the area in Congress, described Mr. Jones as an outsider and opportunist. Mr. Collins’s campaign distributed rape whistles with Mr. Jones’s name on it, alluding to the accusations of misconduct.

Mr. Collins took the stunt further, writing on Twitter that a handgun was a more effective method of self-defense against sexual assault. Mr. Jones then filed a police report claiming Mr. Collins was encouraging violence.