The Republican lawmaker was asked directly by Fox New host Maria Bartiromo on Sunday whether he supports Ms Stefanik for the third-ranking Republican role in the House of Representatives.
“Yes, I do,” he said.
It marks the first time he has publicly supported Ms Stefanik for the position, after he reportedly was caught on a hot mic telling Fox & Friends that he “lost confidence” in Ms Cheney and has “had it with her” following Ms Cheney’s criticisms of her party’s embrace of Donald Trump’s “stolen” election myth.
Ms Cheney voted to impeach Mr Trump after his election fraud narrative fuelled a pro-Trump insurrection at the US Capitol on 6 January.
Ms Stefanik voted against Mr Trump’s sweeping tax cuts in 2017 and was critical of the previous administration’s anti-immigration agenda, including the Muslim ban and construction of a US-Mexico border wall, but she has emerged as a rising figure among GOP lawmakers in a party dominated by an “America First” caucus relitigating election results and mired in culture war grievances against a Democratic majority in Congress and in the White House.
She secured his “complete and total endorsement” following her emphatic support for his spurious legal challenges and false claims of mail-in ballot “irregularities” that allegedly tainted the results of the 2020 presidential election.
Asked whether Ms Cheney’s “never Trump” position influenced GOP opposition to her leadership role in the party, Mr McCarthy told Fox News that “any member can take whatever position they believe in” but signalled that Republicans need to present a “united” front, listing several Democratic agenda items that he opposes.
“What we’re talking about is a position in leadership,” he said on Sunday. “As conference chair, you have one of the most critical jobs as a messenger going forward.”
Ms Stefanik also has support from Minority Whip Steve Scalise, the GOP’s second-ranking lawmaker in the House.
Republicans will convene on 12 May to vote whether Ms Cheney will keep her position in the party.
Earlier on Sunday, Larry Hogan – the Republican governor of Maryland – criticised the “circular firing squad” within his party.
“It just bothers me that you have to swear fealty to the ‘dear leader’ or you get kicked out of the party,” the governor told NBC’s Meet the Press on Sunday.
His comments followed remarks from South Carolina Republican Senator Lindsey Graham, who admitted to Fox News host Sean Hannity on Thursday that it’s unlikely the party can “move forward” without the former president.
“I would just say to my Republican colleagues, can we move forward without President Trump?” he said. “The answer is no.”