"I am embarrassed and humiliated by the conduct of some of the people on my team," the Republican governor said at a news conference in which he patiently took questions from reporters - and answered in his typically blunt fashion - for nearly two hours.
Christie said he fired Deputy Chief of Staff Bridget Anne Kelly, "because she lied to me" when he demanded weeks ago that anyone who knew anything about the episode come forward.
In addition to the firing, Christie also cut ties to former campaign manager Bill Stepien, asking him to withdraw a bid to become the next state GOP chairman.
The governor has denied involvement in orchestrating a massive traffic jam on the heavily trafficked George Washington Bridge - all in the name of political retribution. The governor said he was "blind-sighted" by the scandal. Though he remained adamant that he had no knowledge of the traffic jam, he said he takes full responsibility for the actions of his staff.
"I am responsible for what happened. I am sad to report to the people of New Jersey that we fell short," he said.
Christie focused repeatedly on how upset he was that his staff didn't tell him the truth when asked, saying he was "heartbroken" and "betrayed" by his tight-knit circle of advisers.
"I had no knowledge or involvement in this issue, in its planning or execution," he said of the lane closings. "And I am stunned by the abject stupidity that was shown here."
Emails and text messages between his top aides suggest they engineered a traffic jam to punish the mayor of Fort Lee, N.J.
The emails, released on Wednesday, read: "Time for some traffic problems in Fort Lee" with the response: "Got it."
Kelly hasn't commented. Christie said he hadn't spoken to her since the emails were released, saying he didn't want to be accused of trying to influence a possible witness.
Christie said he is still looking into the traffic-jam episode and will take action against other senior staff members if it is warranted.
The closing of two lanes on the bridge connecting New Jersey and New York snarled traffic for four days in September. Aides rejoiced as drivers suffered. Another email reads: "Is it wrong that I'm smiling?"
The traffic jam happened after Mark Sokolich, Fort Lee's Democratic mayor, reportedly declined to endorse Christie's re-election. For weeks, Christie had asserted that the closings were not punitive, but part of a traffic study. On Thursday, he acknowledged that was a lie, because his staff didn't tell him what it had done.
Christie said he believed his staff in part because he had never heard of Sokolich and had no idea his campaign was even seeking the Democrat's endorsement.
The revelations thrust a regional transportation issue into a national conversation raising new questions about the ambitious governor's leadership on the eve of a second term designed to jumpstart his road to the White House.
At the news conference, Christie brushed off questions about the effect on his presidential ambitions, saying he was too busy governing the state to think about that.
ABC News has obtained a letter from the director of Fort Lee's emergency services. It cites four medical situations where the unnecessary lane closures delayed first responders. In one case, a 91-year-old woman having a heart attack was pronounced dead at a hospital.
"Call the families who were waiting three, four times longer for emergency service agencies when their loved ones were having heart palpitations or when their loved ones had extreme chest pains and were waiting for our ambulance corps to arrive. Do me a favor and call and apologize to thousands of families whose kids were late to the first day of school," said Sokolich.
Christie headed to Fort Lee Thursday to personally apologize to the mayor. He said the meeting was productive.
"I have great respect for the mayor. We had a very good conversation," said Christie.
Christie will be sworn in for his second term as governor in less than two weeks.
Sen. Ray Lesniak wants federal prosecutors to investigate what he calls the abuse of government authority for political gain and the reckless endangerment of lives.
ABC News and the Associated Press contributed to this report.