But he is an aggressive retail campaigner, and in recent weeks traveled Kentucky in a 2001 Chevrolet Suburban with more than 200,000 miles on it; on Tuesday, he turned up at two Chick-fil-A restaurants here in Louisville, shaking hands in a last-minute bid for votes.

For Democrats, more than the governorship was at stake. Kentucky is the last state in the South where Democrats hold a legislative chamber — the Kentucky House — and without the governor’s mansion, their hold on that chamber is in danger.

“This changes the dynamics,” State Senator Robert Stivers, a Republican and the Senate president, said. “Instead of having one leg of the stool, we now have two legs of the stool — and the third leg is very weak.” Later, Mr. Stivers and Mr. Bevin appeared together onstage after Mr. Bevin’s victory speech, leading supporters in a chant of “Flip the House! Flip the House!”

Heading into Election Day, Republicans fretted that Mr. Bevin was frittering away an opportunity. But Bill Stone, a former chairman of the Republican Party in Jefferson County, which includes Louisville, said many analysts had underestimated “how reviled” Mr. Obama and the Democrats are in Kentucky.

Mr. Obama’s health care law was an especially contentious issue in the race, and some see the Bevin victory as a rebuke to Gov. Steve Beshear, a Democrat, who expanded Medicaid under the measure. An estimated 420,000 Kentuckians, nearly 10 percent of the state’s population, now have coverage as a result. Mr. Bevin, a fierce opponent of the health care law, at first said he would reverse it, but has since softened his position and said he would stop enrolling new people but would not take coverage from those who had it.

Kentucky’s shifting political winds were evident on Tuesday at the Shelby County fairgrounds, where voters in Shelbyville, a small city east of Louisville that bills itself as “The American Saddlebred Capital of the World,” were casting their ballots.