House Majority Leader Kevin McCarthy (R-Calif.) introduces Steven Mnuchin, President Trump’s nominee for treasury secretary, during a Jan. 19 Senate Finance Committee confirmation hearing. McCarthy has staked out a crucial role as a trusted Trump loyalist on Capitol Hill. (Andrew Harrer/Bloomberg)

The day before his inauguration as president, Donald Trump scanned the ballroom during a celebratory luncheon at his Washington hotel: “Where’s Kevin?” he asked. “There’s my Kevin.”

It was a brief but telling acknowledgment of a behind-the-scenes political relationship between two GOP power-brokers on opposite ends of Pennsylvania Avenue — Trump and House Majority Leader Kevin McCarthy (R-Calif.) — that has set the stage for a rapid legislative blitz in the early months of the Trump administration.

McCarthy, the No. 2 House Republican, helped forestall an intraparty war during Trump’s campaign, smoothing over tensions between the Republican front-runner and House Speaker Paul D. Ryan (R-Wis.), who repeatedly clashed with Trump on matters of style and substance.

Now Ryan and Trump are largely on the same page, and McCarthy has staked out a role as a trusted intermediary between the new president and House Republicans — one he earned though a decade-long friendship with Ryan and by serving as an unusually early and loyal supporter of Trump’s campaign.

President Trump hosted a reception for House and Senate leaders at the White House on Jan. 23. (Susan Walsh/AP)

“They’ve built a good relationship, and I feel as though I was very helpful in making that happen,” McCarthy said in a recent interview. “I just feel as majority leader, my role is to keep a team together. . . . I think it’s been helpful.”

At the Jan. 19 luncheon, Trump acknowledged as much: “Kevin would call me in the heat of battle. Right, Kevin? And I’d be fighting with Paul,” Trump said, going on to describe how he had patched up his relationship with the House speaker. “Paul Ryan’s done a great job, and Kevin, during the heat of battle, was there for us, and I appreciate it.”

The alliance appears to have been forged back in the heat of the GOP primaries, after McCarthy indicated on MSNBC’s “Morning Joe” that he would have no problem working with Trump as president.

The February 2016 exchange appeared to endear McCarthy to Trump, who called him soon afterward. As McCarthy tells it, Trump phoned him as he sat in church one Sunday morning home in Bakersfield — no blocked number, no secretary, no “please hold for Mr. Trump.”

“It’s just him,” he said. “And we’ve just struck up a relationship over the phone. . . .I’d talk to him about things that were happening that we were going to do in the House . . . so he’d know ahead of time and not be blindsided by anything.”

McCarthy and congressional aides describe a relationship unfolding over the months in scores of impromptu calls and in a June meeting on a Sacramento airport tarmac. As Trump’s Capitol Hill whisperer, McCarthy has taken a place alongside Vice President Pence and White House Chief of Staff Reince Priebus as a key link in GOP relations between the executive and legislative branches.

That has also given McCarthy new relevance in Washington a little more than a year after his steady ascent in House Republican leadership was suddenly halted after former House Speaker John Boehner (R-Ohio) stepped down in 2015.

McCarthy moved to claim the speaker’s chair, but he could not convince the House’s most conservative members to trust him as their leader and stepped aside. Now McCarthy appears to be one of the few on Capitol Hill who has the absolute trust of the one Republican in Washington who matters most.

The two men have bonded over a common approach to politics — light on policy nitty-gritty but heavy on back-slapping, deal-making and personal rapport. Their alliance began many weeks before Trump secured the GOP nomination, at a time when most of senior Republicans on Capitol Hill were treating Trump with kid gloves.

McCarthy, on the other hand, was unusually enthusiastic about the businessman’s prospects. On Feb. 22 — more than two months before Sen. Ted Cruz (R-Texas) dropped out, leaving Trump with the nomination — McCarthy declared on “Morning Joe” that there was “more than a 50 percent chance” Trump would prevail.

Host Joe Scarborough asked McCarthy if he could work with Trump as president. “Oh yeah, I think I can work with Donald Trump,” McCarthy said, then gave a less equivocal answer when Scarborough asked if he could work better with Trump than Cruz, who pushed the 2013 government shutdown.

“That’s an unfair question,” McCarthy said.

McCarthy remained bullish on Trump as he edged closer to the nomination. After a Sacramento fundraiser in early March, he told reporters that Trump could be a boon to down-ballot GOP candidates by boosting voter enthusiasm — at a time when the conventional wisdom was that Trump would drive independents and moderate Republicans away from the polls, spelling disaster for the party.

Trump tweeted his appreciation:“Thank you Kevin. With unification of the party, Republican wins will be massive!”

The relationship intensified after Trump secured the nomination in early May, and Ryan subsequently declined to immediately endorse the GOP nominee .

Ryan ultimately backed Trump a month later, but the tensions between the two men ebbed and flowed over the course of the campaign. Ryan continued keeping his distance from Trump’s most controversial statements and policy proposals. Trump in August appeared to flirt with endorsing Ryan’s primary opponent in his House reelection campaign.

And in October, after The Washington Post published a recording of Trump making crude remarks about women, the rift threatened to split wide open after Ryan told House Republicans that he would not campaign with Trump in the final weeks before Election Day.

That’s when McCarthy said he got on the phone with Trump to try and separate facts from what he considered media-driven hysteria.

“A lot of those things weren’t described properly,” McCarthy said in the interview. “I would talk to [Trump], because I’d see things heating up, and I’d view the press as causing some of this. ‘Paul didn’t say this. The press said he did this; I was on the call, and this didn’t happen.’ I think he appreciated that.”

“I’d also tell Paul, ‘Hey, he’s not doing that,’” he added. “Get ’em back together.”

What gave McCarthy credibility with Trump were ongoing gestures of loyalty, including regular television appearances backing Trump and his service as a Trump delegate and prime-time speaker at the Republican National Convention.

With Ryan, McCarthy can call on a long relationship they forged as fellow “Young Guns” ascending the GOP ranks together.

Ryan has now patched up his relationship with Trump, noting in recent interviews that the two speak on a near-daily basis. But there are indications of the continuing esteem McCarthy holds in Trump’s orbit.

It was McCarthy last month, as the highest-ranking California Republican in Congress, who introduced Treasury Secretary nominee and fellow Californian Steven Mnuchin to the Senate Finance Committee. And two former McCarthy aides, Ben Howard and Tim Pataki, have joined Trump’s Office of Legislative Affairs and are now working out of office space inside McCarthy’s suite on the first floor of the Capitol.

McCarthy was also among the congressional leaders who were invited to the White House during Trump’s first week in office to discuss his legislative agenda. But he declined to say what exactly he has discussed with Trump since his inauguration.

“I find a lot of people want to go out and talk about their relationship with Trump,” McCarthy said in the interview. “I just want to help him.”