The founder of a string of auto repair shops won a majority of the Republican vote, meaning there's no need for additional rounds of voting under the voting system used in a statewide primary for the first time in U.S. history.
"I think Mainers have spoken," Moody said. "They want a businessperson, an outsider. And they're not ready to turn Augusta back over to the politicians."
The Associated Press did not call the Democratic primary as no candidate was close to the majority needed to be declared the outright winner, so more tabulations are required next week under ranked-choice voting. Last-place candidates will be eliminated and votes reallocated until there is a winner, a process that may take more than a week.
According to returns tabulated by The Associated Press, Moody was leading state Sen. Garrett Mason by about 30 percentage points as midnight arrived and more than 60 percent of the expected vote was counted.
A field of 11 Democrats and Republicans sought their party's nomination for the opportunity to succeed LePage, who streamlined government, lowered taxes and trimmed welfare but also angered some with his harsh tone and policy decisions.
Moody, who as a high school senior founded a successful chain of auto collision centers, has cast himself as the "outsider businessman" in the style of LePage and Republican President Trump.
Moody, 58, has served as a trustee at the University of Maine System and the Maine Community College System. He unsuccessfully ran for governor against LePage as an independent in 2010, and enrolled in the Republican Party last year.
"I don't have maybe baggage so to speak politically," Moody said. "I think Maine people want a fresh start."
In the Democratic primary, Attorney General Janet Mills and attorney Adam Cote both had more than 25 percent of the vote with more than 60 percent of the expected vote counted.
LePage on Tuesday, a long-time opponent of ranked voting, called the election overhaul the "most horrific thing in the world." He threatened not to certify Tuesday's election results, but Maine's top election official quickly said that the governor can't stop primary election results from moving forward.
Democratic Secretary of State Matt Dunlap said the governor could refuse to sign a proclamation of the results but that still wouldn't stop the nominations from taking effect.
"He can bluster," Dunlap said.
LePage, a fiscal conservative who has compared his style to President Donald Trump's, was elected in 2010 in a multicandidate race amid a Tea Party wave of conservatism.
He declined to endorse a candidate, but his family has ties to Moody. LePage's daughter, Lauren, worked for Moody's campaign, and his wife, Ann, endorsed Moody in campaign ads.
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