The “Big Four,” from left: John Boehner, Mitch McConnell, Harry Reid and Nancy Pelosi. (Alex Brandon/AP)

The “Big Four” have broken up.

After Rep. John A. Boehner (R-Ohio) cast his last vote Thursday, the teary-eyed House speaker waved to his colleagues, saluted his successor and headed into retirement.

He left behind three other party leaders he knows all too well. They’ve fought over war and peace, a great recession and an economic recovery, leading to huge wins for Democrats and monumental wins for Republicans.

For almost nine straight years, Boehner, Rep. Nancy Pelosi (D-Calif.) and Sens. Mitch McConnell (R-Ky.) and Harry M. Reid (D-Nev.) have led their respective caucuses — longer than any other quartet of party leaders in congressional history.

Since January 2007, the Big Four, as they are referred to at the White House, have come together for everything from Oval Office meetings during global crises to institutional ceremonies such as awarding the Congressional Gold Medal.

About as different personally as any four people could be, Boehner and his three cohorts have learned each other’s rhythms, tactics and bargaining ploys, and shared dead-serious moments of candor. They have overseen a historically unpopular Congress, no matter which party held the majority.

They let the federal government slip into a 16-day shutdown in 2013, their standoffs almost led to a U.S. default that would have crippled global markets, and one failed vote during the 2008 Wall Street crisis precipitated the largest one-day stock drop in history.

Overall, the toxic tone of partisanship marked much of this group’s tenure, and in his maiden speech as the new House speaker, Paul D. Ryan (R-Wis.) pitched himself as someone who would try to move beyond the recent political warfare, “wiping the slate clean.”

Yet if not for the battle-tested negotiations of the four veteran leaders, things might have been a lot worse.

“Very well, I know all of them very well,” Boehner said in an exit interview with congressional media. He acknowledged that one motivation in forging this week’s budget deal was that Ryan would have had to make in­cred­ibly difficult decisions in his first week on the job without having any real relationship with Pelosi, Reid and McConnell.

“When you throw somebody new into the mix at the last second and something has to happen, it really isn’t fair for them or frankly for the others,” Boehner said.

The speaker’s departure comes 14 months ahead of Reid’s retirement, when he is expected to be replaced by Sen. Charles E. Schumer (N.Y.) as Democratic leader.

This season of change on Capitol Hill produced an unusual outpouring of bipartisan respect this week as the other leaders considered life without Boehner.

“I hope that John Boehner tells his children and his grandchildren that his legacy, as far as I’m concerned, is one of absolute honesty. He never, ever misled me,” Reid, the onetime Senate majority leader now serving as minority leader, told reporters Wednesday.

Before congratulating Ryan on his election Thursday, Pelosi praised her sparring partner in so many House debates: “John Boehner talked about the American Dream. John Boehner, you are the personification the American Dream.”

By that point Boehner was standing behind the back row, wiping his eyes and nose, fighting back tears. He had just cast his last vote, for Ryan to succeed him.

A few minutes later, Boehner saluted his troops and exited the chamber, ending the eight-year, 10-month run of Boehner, Pelosi, McConnell and Reid as the stewards of the institution.

Their collective tenure will be remembered for a constant series of negotiations, first with President George W. Bush and then President Obama, that focused on trying to avert fiscal calamity.

With both presidents, talks at the White House often collapsed ignominiously — Bush’s treasury secretary ended up on one knee in the West Wing pleading with then-Speaker Pelosi to not give up on the 2008 bailout — only to be resumed later in the Capitol, where the four leaders hashed out some last-minute deal.

As Christmas 2012 approached and a massive set of tax hikes and spending cuts loomed, Boehner blew up at Reid in an expletive-laced tirade outside the Oval Office and basically ended the “Big Four” discussions in person with Obama. A week later, McConnell wheeled and dealed from his Capitol suite, talking by phone with Reid and Vice President Biden to craft a compromise.

They couldn’t be much more different: Pelosi, 75, the extroverted Italian grandmother from San Francisco; McConnell, 73, the introverted only child raised in the South; Reid, 75, the soft-talking Mormon from a tiny mining town in Nevada; Boehner, the gregarious Midwesterner from a family of 12 kids with a penchant for Camel cigarettes and an extra glass of merlot.

If they were a four-piece band, Pelosi would be the lead guitarist, providing the energy and drive; McConnell, the bass guitarist, quietly holding the act together; Reid, the drummer pushing his silent rage to make things work better.

Boehner, of course, would be the lead singer, full of so much passion that he always reached for the most virtuoso performance, even if it often meant burning up in spectacular failure.

Their odd chemistry was forged, in part, from assuming power in similar circumstances: political failure. Pelosi took command of House Democrats in January 2003 after a fifth straight election left them in the minority. Reid assumed the top job for Senate Democrats after the 2004 elections left them deep in the minority.

Boehner and McConnell took the top jobs after the 2006 election thumping that left Republicans in the minority amid ethics scandals and the unpopular Iraq war.

Their dealings were never pretty but were usually successful.

When the first House vote collapsed on the Wall Street bailout, amid Boehner’s inability to bring along enough Republicans, Reid and McConnell patched on a bunch of popular tax breaks and other items that made a do-over vote successful. “I gave him some ideas about how to juice it up a little bit, ” Boehner recalled Wednesday of his 2008 talks with McConnell.

The four leaders had some of their fiercest clashes in the first 18 months of Obama’s presidency as massive Democratic majorities pushed through health and banking laws with hardly any Republican support. The health-care debate ended with Boehner’s floor speech asking lawmakers whether they could call the legislation free of backroom deals cut by Pelosi.

“Hell no, you can’t!” Boehner screamed moments before the law won final approval.

By July 2011, after a landslide midterm victory handed him the speaker’s gavel, Boehner ditched the other three leaders and tried to cut a $4 trillion grand bargain on his own with Obama in secretive visits to the White House.

After multiple collapses, Reid and McConnell swept in, along with Biden, to close out the talks. On Wednesday, during a wistful goodbye visit to the speaker’s office, McConnell and Boehner recalled the final Sunday before a deadline on the Treasury’s borrowing limit that, if breached, could have led to global financial collapse.

Boehner burst into laughter when he considered how close the leaders were to not reaching a deal and a U.S. default on its debt: “We were pretty close.”

In their odd negotiating style, Boehner spent that day in his office watching the final round of a PGA Tour golf event, McConnell in his office watching baseball. It all worked out, somehow.

The only other congressional quartet to lead their caucuses together for more than five straight years — Tom Foley (D-Wash.) as speaker, Bob Michel (R-Ill.) as House minority leader, George Mitchell (D-Maine) as Senate majority leader and Robert Dole (R-Kan.) as Senate minority leader — ended their act together in 1994.

Now, after one final budget deal pieced together over the past few weeks, today’s record-setting “Big Four” are losing their lead singer. The much younger Ryan, 45, will soon join the group, with Schumer waiting in the wings.

Everyone is a little unsure about how it will come together.

“People will figure it out. People will get used to it. People will get used to new players,” Boehner said, reflecting later on his time at the top. “It’s been a good run.”