Christie said he made his final decision last night and told those closest to him this morning. He said he went to the bed last night "knowing exactly what I wanted to do" for the first time in weeks.
He declined the chance to close the door on a future presidential run, saying he is "not going to preclude any employment in the future."
The New Jersey governor said that he decided to revisit his initial vows not to run after being called upon to change his mind in recent weeks, saying he "felt an obligation to earnestly consider" the appeals. He said he "explored the options" and thought seriously about running but that "in the end, what I've always felt was the right decision remains the right decision today."
"I have a commitment to New Jersey that I will not abandon," Christie said during a lengthy, nearly hour-long press conference, adding: "New Jersey, whether you like it or not, you're stuck with me."
"The deciding factor was it did not feel right to me, in my gut, to leave now when the job is not finished," said Christie, who made his remarks at the New Jersey statehouse.
Christie said the calls to enter the race, which were driven by wealthy Wall Street donors dissatisfied with the Republican field, were "unbelievably humbling and inspiring," adding that he "felt an obligation to earnestly consider" the advice both of those donors and of the everyday Americans calling on him to run.
"Can you imagine?" Christie said of a presidential candidate who would tap him for the vice presidential slot. "The guy would probably want to get a food taster."
Christie's brash style has made conservatives around the country swoon, and he has shown an ability to take on unions and fight for budget cuts while remaining relatively popular, unlike many other Republican governors. A Quinnipiac University poll released Tuesday found Christie and Mitt Romney tied at the top of the polls with 17 percent support from Republican voters, followed by Herman Cain at 12 percent and Rick Perry at 10 percent.
Yet there were serious obstacles to a Christie run. The first was the fact that his position issues like climate change (he called it "real"), immigration, gun control and the notion of "creeping Sharia law" (Christie deemed such concerns "crazy" "crap") put him at odds with much of the Republican base. That would have posed particular problems for Christie in a pair of early states -- Iowa and South Carolina.
Timing may have proved to be more important. Christie would have gotten into the race less than three months before voters are expected to begin going to the polls. (The primary calendar remains in flux, but voting looks likely to kick off in early January.) He would have needed to develop a ground game in key early states, develop a platform and establish his fundraising network in an extremely short period of time, all while preparing for regular debates against his opponents and making himself better known to the American people.
And that would have been harder than you might think: Despite the deafening buzz around Christie in political circles in recent weeks, aout Tuesday morning found that 70 percent of voters - including 63 percent of Republican primary voters - didn't yet have an opinion about him. Asked if they would like to see Christie join the field, Republican primary voters offered a mixed response: 32 percent said yes, 38 percent said no and 30 percent said they didn't know.
Christie insisted Tuesday that family concerns were not a factor, saying the only issue was that he did not feel right leaving his job in New Jersey. He said his wife and children "were completely behind me running if that's what I want to do." He added that his wife woke him up weeks ago and said "if you want to run, go for it, and don't worry about me and the kids, we'll be fine."
Christie, who became governor in 2010, also criticized President Obama in his remarks, saying the president "failed the leadership test."
"The country will be better if President Obama is a one-termer," he said.
And he addressed the fact that there has been discussion over his weight in recent weeks, saying the jokes did not bother him.
"I'm not particularly self-conscious about this," he said, adding: "It's not a news flash to me that I'm overweight."
While Christie said he found many of the jokes about his weight funny, Americans should "look down upon" the "people who pretend to be serious commentators" who suggested he couldn't be president because of his weight.
"The people who wrote [that] are ignorant people," said Christie.
"To say that because you are overweight you are therefore undisciplined---I don't think undisciplined people get to achieve great positions in our society," he said.
Christie said he believed he could have won the race, citing as evidence the fact that people were taking shots at him before he even entered. He concluded the press conference by saying he needed to get back to his duties as New Jersey governor.
"I've got a job to do," he said.