Debate about whether Pierson should stay or go had been growing in the wake of a security breakdown at the White House last month and other revelations in recent days that have further damaged the agency's reputation.
White House spokesman Josh Earnest said at the daily briefing that Pierson met with Homeland Security Secretary Jeh Johnson earlier in the day and offered to step down because she felt it was in the best interest of the agency. The secretary and President Barack Obama agreed with that assessment, Earnest said. Obama then telephoned Pierson and thanked her for her 30 years of service.
Despite the incident on Sept.19 when a man with a knife in his pocket jumped the fence at the White House and made it inside the building, Obama had maintained confidence in the Secret Service and in Pierson, according to Earnest.
Just hours after Pierson testified on Capitol Hill about the incident on Tuesday, another story broke about protocols not being followed.
This one, according to the Washington Post, involved a private security firm employee riding an elevator with Obama during a trip to the Centers for Disease Control and Prevention in Atlanta.
That violated protocol, people familiar with the incident anonymously told the newspaper, because advance screening with the help of databases is supposed to keep people with weapons or criminal histories away from the president during public events.
This man had both — he was carrying a gun and had three convictions for assault and battery — but somehow slipped through the screening cracks. The Secret Service agents didn't know he was carrying a gun until afterward when they questioned him.
The elevator incident occurred three days before the White House fence jumping, which prompted Tuesday's committee hearing and renewed scrutiny of the Secret Service.
Pierson didn't mention the Atlanta event during her three hours of testimony, when she was pounded with questions about the security failure at the White House and about morale and leadership.
Critics 'not impressed' by Pierson
She admitted that she approved a press release about the incident that suggested the accused intruder, Omar Gonzalez, was apprehended just inside the White House front door. Only through media reports was it later revealed that he knocked down an officer inside and made it deep into the building.
On top of the security breaches themselves, Pierson's agency is coming under fire for how it is handling their fallout and suspicions about attempted coverups are growing.
"I wish to God you protected the White House like you're protecting your reputation here today," Representative Stephen Lynch scolded the director.
Information is trickling out through whistleblowers, not from the agency, which shows the force isn't being transparent and that some employees aren't comfortable talking to their managers, some members of Congress are saying.
Despite Pierson's promise to redouble her efforts to address what she called challenges, but others call scandals, over the last few years, several lawmakers said they weren't satisfied with her performance at the committee and were losing faith in her.
"I am not impressed and I was extremely disappointed," Representative Elijah Cummings, the ranking Democrat on the committee, said on MSNBC Wednesday morning. "I have come to the conclusion that my confidence and my trust in this director, Ms. Pierson, has eroded. And I do not feel comfortable with her in that position."
In a later interview on CNN, Cummings appeared willing to give Pierson some more time to "restore trust" and fix the broken Secret Service culture. If she can't, she's got to go, he said.
Time for Pierson to quit or be fired
Another member of the committee, Representative Jason Chaffetz had already made up his mind: "I think it's time that she be fired by the president of the United States or that she resign," he said on Fox News.
Representative Mark Meadows said there are problems with leadership, training and culture and that it's hard for Pierson to establish "credibility." He and others "will call for her resignation," he said.
Some of the Secret Service scandals, such as the excessive drinking and prostitutes in Colombia, the White House party crashers, and the mishandled investigation of bullets fired at the White House, happened before Pierson was appointed by Obama in 2013.
She was brought in to repair the bruised reputation, but these latest incidents are only causing further damage and leading to questions about her leadership.
Some were finding it hard to believe that Obama would maintain confidence in Pierson. How confident could he be when multiple layers of security failed and a man with a knife was able to get deep inside his home, which is supposed to be one of the safest buildings in the world?
Earnest was pressed Tuesday to explain why exactly the president had confidence in Pierson. Because she was willing to testify before Congress, had taken responsibility for the Sept.19 breach and had promised to make the necessary changes to prevent it from happening again, he responded.
"That is a sign of leadership," Earnest said. Pierson did not offer her resignation when she met with Obama last week to brief him on the intruder.
Republican Representative John Mica came to Pierson's defence at the committee and blamed Congress for not helping her make all of her intended changes. He said she approached the committee a long time ago and asked for more authority to fire employees — something that can be difficult to do in government agencies — and for changes to the education and training standards. The requests haven't been dealt with, he reminded his colleagues.
The ranking members of the committee say they intend to ask Congress for an external review panel to take a hard look at overhauling the Secret Service.