WEST BLOOMFIELD, Mich. — Ron Weiser, a wealthy real estate developer from Ann Arbor, was elected chair of the Michigan Republican Party on Saturday, bringing along a vice chair who has caused consternation among some factions of the party because of her fierce support of former President Donald J. Trump.

The vote from more than 2,000 party delegates did little to heal the deep divide in the party that surfaced this week when Laura Cox, the chair of the party for the last two years, jumped back into the race at the last minute, saying that Mr. Weiser had used $200,000 in party funds as a payoff to get a candidate out of the race for secretary of state in 2018.

The election partially hinged on who was the more loyal supporter of Mr. Trump, with supporters of Mr. Weiser saying Ms. Cox had failed the party when Joseph R. Biden Jr. won the state by more than 154,000 votes, flipping a key state that went for Mr. Trump in 2016.

Mr. Weiser, who is also a member of the University of Michigan Board of Regents and a prolific donor to both the Republican Party and the university, has been chairman of the state party twice before — from 2009 to 2011 and 2017 to 2019.

He won the election for party chair by a two-to-one ratio. In a statement after the vote, he said: “The skirmishes of yesterday are over. Our focus now rests on the great challenges before us: Rebuilding our party,” and defeating Gov. Gretchen Whitmer and other Democratic state officials he called “far left radicals.”

But the battle over what degree of loyalty to Mr. Trump is appropriate revolved less around Mr. Weiser than his designated choice for vice chair of the party, Meshawn Maddock, who formed the Michigan Conservative Coalition and is the head of Women for Trump in Michigan.

She was a vocal opponent of the Michigan election results and protested at the TCF Center in Detroit while absentee ballots were being counted there. She spoke at a Trump rally in Washington on Jan. 5 and had organized dozens of Trump supporters headed to the rally on Jan. 6 that preceded the attack on the U.S. Capitol.

While she condemned the violence at the Capitol, her participation in the events leading up to the riot led students and faculty members at the University of Michigan to sign petitions calling on Mr. Weiser to resign from the Board of Regents, a seat he was elected to in 2016.

Their ascension to the leadership of the Michigan Republican Party is another indication that the party at the state and local levels is still largely in the grip of the former president.

Also elected to leadership positions were two women, Marian Sheridan and Diane Shindlbeck, who along with Ms. Maddock formed Michigan Trump Republicans after he was elected in 2016. The group organized rallies, caravans and forums across the state to drum up support for his re-election bid.

“The Republican Party has evolved into the Trump party, and from the standpoint of Weiser, it brought a lot of new people into the party, and it’s his job to keep them there,” said Tom Shields, a Lansing-based Republican political consultant with Marketing Resource Group. “And using Meshawn as the conduit to the grass roots is smart.”

The race to lead the Michigan Republican Party was thrown into disarray this week when Ms. Cox, the current chair, took aim at Mr. Weiser for what she called a “sleazy payoff” to a party official to get him to drop out of the race for secretary of state in 2018.

Ms. Cox claimed that Mr. Weiser had sent $200,000 to Stan Grot, the clerk of Shelby Township in Macomb County, so that Mary Treder Lang would face no opposition for the Republican nomination for secretary of state, Ms. Cox said. She said it was not only unethical but could be a violation of state campaign finance laws. She turned over her complaint to the secretary of state, Jocelyn Benson, a Democrat, who could open an investigation into the state Republican Party.

“If you think what Ron did is OK, then vote for him,” Ms. Cox wrote in an email to party delegates on Thursday. “If you don’t want back room deals and secret payoffs, then vote for me.”

In a social media post, Mr. Weiser called the accusations from Ms. Cox “a shameful attempt to destroy our party with unfounded and reckless conspiracy theories so that she can get back in the chair’s race and save her paycheck.”

He said the money paid to Mr. Grot had been for organizing work he did in Macomb County, a key Republican stronghold, during the 2018 election cycle.

On social media, Ms. Maddock called Ms. Cox “a bitter, sore loser who failed our president in the 2020 elections.”

Ms. Cox told delegates she would resign from her position in April if they elected her as chair, giving the party’s executive committee the chance to name her replacement at its next meeting.