E-mails and texts released Wednesday pointed to involvement by a deputy chief of staff, Bridget Anne Kelly; Christie's former campaign manager, Bill Stepien; and two of his appointees to the Port Authority, Bill Baroni and David Wildstein.
"I am embarrassed and humiliated by the conduct of some of the people on my team," Christie said. Later, describing his emotions, he said: "I am a very sad person today."
It was a day that cast Christie in the national limelight - but not the kind he is used to. The Republican governor, who has been viewed as a likely candidate for the presidency in 2016, saw his stature rise after trouncing Democratic State Sen. Barbara Buono in a 22-point blowout in November.
This time, CNN fixed its cameras on a contrite Christie, telecasting his repeated expressions of regret - "I am heartbroken," "I am extraordinarily disappointed" - as well as his assurances that he played no role in the scheme that shut access lanes from Fort Lee to the bridge, delaying school buses and emergency responders.
Later in the day, Christie traveled to Fort Lee to apologize to Mayor Mark Sokolich - a man whom Christie said earlier he would not have been able to recognize "until yesterday, when I saw his picture on TV."
A former U.S. attorney, Christie found himself fielding questions about an investigation into his administration by the U.S. Attorney's Office.
He was asked about the impact of the controversy on his national aspirations. As usual, Christie said he was "enormously flattered" by speculation he would run for president, but had made no decision.
And there was a new question: Had he considered resigning?
"Oh, God, no," Christie responded. "That's a crazy question, man."
While he acknowledged there would be "some crisis in confidence," he said, "I don't believe I've lost the trust of the people of New Jersey."
Democrats said they planned Friday to release hundreds of pages of additional documents.
Previously, Christie had denied any involvement by his staff in the situation and dismissed the possibility of any plot.
Wildstein and Baroni, a former state senator, resigned from the Port Authority last month after Baroni testified before a legislative committee that the lane closures had been ordered by Wildstein as part of a traffic study.
Documents subpoenaed by lawmakers and obtained by reporters Wednesday showed that in an e-mail Aug. 13, Kelly wrote to Wildstein: "Time for some traffic problems in Fort Lee."
"Got it," Wildstein immediately responded.
In a text message sent during the closures, an unnamed person said of children stuck in traffic: "They are the children of Buono voters," referring to Christie's opponent in the November election.
Christie said the "political overtones" and language of the messages was unacceptable. In one e-mail, Stepien called Sokolich an "idiot."
"Ultimately, I am responsible for what happens under my watch: the good and the bad," Christie said.
The U.S. Attorney's Office said Thursday that it was reviewing the incident to determine whether federal laws were involved.
Christie said at the news conference that he had "absolutely nothing to hide."
"My instruction to everybody will be to cooperate and answer questions," he said of the U.S. attorney's investigation.
Although he said he was caught off guard by the disclosures, Christie said he had previously pressed his staff on the bridge incident as questions continued to arise.
Before a news conference four weeks ago - when he pledged no involvement by his staff in the situation - Christie said he told staff members that they had one hour to report any new information. No one did, he said.
"I'm incredibly loyal to my people," he said. "And I expect in return their honesty and their candor and their loyalty."
Of Kelly, he said, "I terminated her employment because she lied to me."
Throughout the news conference, Christie emphasized the hurt he felt after getting a call at 8:50 a.m. Wednesday from his communications manager.
Christie, who said he had just finished a workout at home with his personal trainer, looked on his iPad and saw a report posted by the Bergen Record about the 22 pages of documents that surfaced Wednesday. Other reports quickly followed.
"You can only imagine, as I was standing there in my bedroom with my iPad . . . how incredibly sad and betrayed I felt," he said.
As the disclosures exploded into a national news story, Christie remained silent for much of Wednesday. Late in the day, he issued a statement via e-mail saying he was "outraged and saddened."
Though he remained out of the public eye when the news broke, Christie said he responded quickly - a point he repeated Thursday. By 7 p.m. Wednesday, Christie said, Stepien had been asked to leave his organization.
By 9 a.m. Thursday, Christie said, he had fired Kelly. "That's pretty swift action for a day's work."
Christie said he did not talk to Stepien or Kelly about the issue before firing them, saying he did not want to interfere with the ongoing legislative investigation.
Of the Democrats leading the investigation, Christie said, "They have every right to do what they're doing, given what was revealed yesterday. I'm certainly not going to question that."
Assemblyman John Wisniewski (D., Middlesex) said Thursday that lawmakers would continue their work.
"We need to hear from Bridget Kelly. We need to hear from Mr. Stepien. We need to hear from Mr. Drewniak" - Michael Drewniak, the governor's press secretary, Wisniewski said, also mentioning the governor's chief counsel, Charlie McKenna.
"I'd like to see full cooperation," Wisniewski said. "I don't think this committee should have to resort to subpoena authority."
On Thursday, the Assembly transportation committee held Wildstein in contempt of a subpoena requiring him to answer questions about his role in the lane closures.
Wildstein invoked his right to remain silent under the U.S. and New Jersey Constitutions. But the committee voted that in doing so, he violated New Jersey law.
His attorney, Alan Zegas, cited the federal investigation into the lane closures and said his client had the right to not say anything "that could be used by prosecutors were they to charge him."
Earlier Thursday, a judge denied Wildstein's motion to quash the subpoena.
Wildstein remains under subpoena, and the committee has asked his attorney to disclose previously redacted documents.
Christie plans to have one-on-one discussions with his staff. He said he was confident that staff members whose names appeared in the e-mails "had no prior knowledge or involvement in this situation."
One e-mail indicates that Drewniak, Christie's press secretary, had dinner with Wildstein in December two days before releasing a statement announcing Wildstein's resignation.
Inquirer staff writer Andrew Seidman contributed to this article.