The Washington Post's Abby D. Phillip explains the circumstances around Rep. Debbie Wasserman Schultz's decision to resign as chair of the Democratic National Committee. (Peter Stevenson/The Washington Post)

What was supposed to be a morning of personal triumph for Debbie Wasserman Schultz — rallying her home-state delegation before opening the Democratic National Convention she had orchestrated — suddenly became one of humiliation.

“Shame!” people in the room jeered as the congresswoman addressed a Monday breakfast of the Florida delegation. “Shame!”

It was a cringe-worthy, nationally televised spectacle that exposed deep divisions within the Democratic Party and reopened raw wounds from the Hillary Clinton-Bernie Sanders primary battles. By the afternoon, Wasserman Schultz had disappeared here in Philadelphia, after also giving up her speaking slot and her ceremonial role gaveling the convention to order.

On Sunday, Wasserman Schultz had announced plans to resign as chairwoman of the Democratic National Committee effective Friday, after leaked emails among her and her top aides revealed favoritism for Clinton during the presidential primaries.

The party’s turmoil drove conversation in Philadelphia’s sweltering streets Monday, with elected officials and delegates agitated and alarmed that it was over­shadowing the convention’s kickoff. The four-day production had been carefully choreographed to be a week-long celebration of unity behind Clinton, about to become the first woman to be a major party’s presidential nominee.

Supporters of Bernie Sanders gathered outside City Hall in Philadelphia on Monday. Most vowed to never vote for Hillary Clinton, despite Sanders's encouragement to do so while speaking a few blocks away. (Alice Li,Jayne Orenstein/The Washington Post)

“It’s like a blister, it just popped. It had been festering and festering and festering,” John Morgan, a Florida-based Clinton donor, said of Wasserman Schultz’s rocky tenure, which he has long criticized.

Donna Brazile, the incoming interim party chair, acknowledged the rowdy atmosphere.

“It takes time to heal, time to come together,” she said in a brief interview backstage at the Wells Fargo Center. “I’m confident that we can find common ground, which is what’s most important.”

Brazile said she has been apologizing to Sanders’s advisers and to disgruntled party donors. “I’ve told them that we will make sure our system gets better, make sure our practices get better and make sure our email gets more secure,” she said. “I’ve been in this party for 40 years. We love this party, and we’re going to do what needs to be done.”

But Wasserman Schultz’s departure from center stage was not enough to quell the party’s tumult. The DNC has begun an investigation of internal emails following the compromise of its network by hackers, and party officials braced for thousands more potentially embarrassing messages to surface in the coming days or weeks.

There is also uncertainty about how long Brazile might stay on as chair. She said she is willing to serve through the November election but does not want the position permanently, and discussions are underway about who might step in next.

Many senior Democrats said additional firings may be necessary.

Clinton’s campaign manager, Robby Mook, said the DNC should “take appropriate action” based on the findings of its review. Other Democrats were more direct.

“Down the road, staffers are going to have to be part of the consequence, part of the casualties,” said Rep. Raúl M. Grijalva (Ariz.), co-chairman of the Congressional Progressive Caucus and a Sanders supporter. “It’s one thing to take away the titular head, but it’s also appropriate to address those who were navigating and writing these emails.”

Virginia Gov. Terry McAuliffe, a former DNC chair, said he was outraged. “If I had been chair, they would have been fired within five minutes,” McAuliffe said, although he expressed sympathy for Wasserman Schultz, noting that he had a drink with her Sunday night.

The Sanders contingent felt vindicated, having long seen Wasserman Schultz as a Clinton agent masquerading as an impartial referee. Even as the senator from Vermont urged his followers to unify behind Clinton, they displayed remarkable dissent all afternoon, and the convention was awash in anti-Clinton and anti-trade chants.

“This controversy aggravates all of the fears and suspicions that millions of Americans who supported Bernie Sanders had during the Democratic primaries and caucuses,” said Robert Reich, a Sanders backer who was secretary of labor in Bill Clinton’s administration.

Veteran party figures said it is understandable that Sanders and his followers would not trust the DNC, considering Sanders has largely worked outside of the party structure, running as an independent in Vermont.

“I can see their claiming foul, but maybe they should have early on had some overture and closeness to the DNC by having people connected there over the years,” said William M. Daley, a former White House chief of staff to President Obama. “Because he never ran as a Democrat, there was no connection, whereas the Clintons for the last 25 years have had hundreds of people on the DNC, staffing the DNC, fundraising for the DNC.”

Clinton allies were hopeful Monday that after four nights of speeches, the tensions over Wasserman Schultz and her DNC staff would be forgotten.

“Who endorses whom when, where and why, who’s the chair of the DNC — it really doesn’t matter,” House Minority Leader Nancy Pelosi (D-Calif.) told reporters at a Bloomberg Politics event.

One Democrat close to the Clintons, who requested anonymity to speak candidly, said of the Wasserman Schultz episode, “I think this is much of a tempest in a teapot, but it’s the heat of politics, and the teapot is whistling.”

Complicating the party establishment’s push to bind together their ranks Monday were fuming donors who, while mostly aligned with Clinton and the DNC, felt themselves dragged into a spotlight they did not seek. Many were upset that their exchanges with party leaders were leaked — and by the way staffers belittled and mocked them in private correspondence.

The emails exposed a DNC culture that at times, some Democrats said, was built around sustaining Wasserman Schultz’s image and national standing more than the health of the party at large.

“It was all about her, first, second and third,” Morgan said. “You had a very partisan person who had many different agendas, but none of them was what’s in the best interest of party and all of them were what’s in her best interest. That’s the dysfunction in a thumbnail.”

The DNC leadership sought to move on, issuing a public apology to Sanders.

“These comments do not reflect the values of the DNC or our steadfast commitment to neutrality during the nominating process,” the statement read. “The DNC does not — and will not — tolerate disrespectful language exhibited toward our candidates. Individual staffers have also rightfully apologized for their comments, and the DNC is taking appropriate action to ensure it never happens again.”

In Wasserman Schultz’s absence, Baltimore Mayor Stephanie Rawlings-Blake, a DNC vice chairwoman, gaveled in the convention Monday afternoon and was named secretary of the convention.

Though she remained out of the public eye most of the day, Wasserman Schultz kept parts of her political schedule. Hilary Rosen, a strategist and friend of Wasserman Schultz, said the party chairwoman attended a restaurant gathering hosted by donor Stephen Bittel, where she grew emotional as she thanked him and other friends.

Rosen said Wasserman Schultz planned to stay in Philadelphia throughout the convention, disputing chatter that she might fly home to Florida.

The congresswoman told the Sun Sentinel newspaper in Florida she had “decided that in the interest of making sure that we can start the Democratic convention on a high note that I am not going to gavel in the convention.”

Earlier in the morning, the Florida delegation breakfast devolved into chaos, with Sanders supporters berating her. Wasserman Schultz tried to quiet the crowd.

“If I could ask everybody to settle down,” she said. Moments later, she repeated herself: “All right everybody, now settle down. Settle down, please.”

They did not. The boos and jeers and cries of “shame” continued until Wasserman Schultz exited. It was the last time many people saw the party chairwoman.

Jenna Portnoy contributed to this report.