Carey's win over a crowded primary field that included better-established candidates showcased Trump's power within the party at a key moment.
A week earlier, a Trump-endorsed candidate had lost a runoff election in Texas to another Republican -- calling into question the former President's influence now that he is out of office and casting some doubt on his ability to settle scores with old rivals in next year's midterm elections.
Carey will be favored to win the November 2 special general election against state Rep. Allison Russo, who CNN projects will win the Democratic nomination, in the heavily Republican district that includes part of Columbus and the more rural, conservative area to its south. The winner will replace former Republican Rep. Steve Stivers, who resigned earlier this year to take a job with the Ohio Chamber of Commerce.
Trump issued several statements backing Carey, and a Trump-aligned super PAC spent $350,000 on the race.
In a July 15 statement, Trump said Carey was doing well against a "gang of RINOs" -- short for "Republicans in name only" -- in the race.
Twelve days later, Trump issued another statement supporting Carey, saying he didn't even know who the other candidates were. "But I do know who Mike Carey is—I know a lot about him, and it is all good. Mike Carey is the only one who has my Endorsement and he's the one I feel will do the best job for Ohio, and for the United States," Trump said.
However, other influential Ohio and national figures backed different candidates -- creating an unpredictable environment, particularly in a low-turnout special election.
Stivers himself endorsed state Rep. Jeff LaRe, a former sheriff's deputy, while Ohio Right to Life endorsed state Sen. Bob Peterson.
Kentucky Sen. Rand Paul endorsed Ron Hood, a former state lawmaker who has taken up Paul's criticism of Dr. Anthony Fauci, the nation's leading infectious disease official. Hood had vowed to work closely with far-right Georgia Rep. Marjorie Taylor Greene and said his first act would be to join the House Freedom Caucus.
Debbie Meadows, the wife of former Trump chief of staff Mark Meadows, and several other influential conservative activsts are aligned with Ruth Edmonds, a former Columbus NAACP president and Black pastor who has positioned herself as an opponent of critical race theory.