The reaction among political observers was mixed.
"I find it enormously surprising," said Brigid Harrison, a political scientist at Montclair State University.
Harrison said she thought Christie would "use his gubernatorial election as a mechanism by which he could spend lots of money in the broader mid-Atlantic region with an eye on 2016," referring to a potential presidential bid.
With unlimited fund-raising, the popular governor could have shaped public opinion early on by advertising in big media markets such as Philadelphia and New York City, as well as in key primary states and battlegrounds such as New Hampshire and Virginia, she said.
Even as Christie enters the donation-matching program, Harrison said, outside groups such as Americans for Prosperity, which opened a branch in Cherry Hill on Tuesday, could do the heavy lifting for fund-raising and advertising.
But Ben Dworkin, director of the Rebovich Institute for New Jersey Politics at Rider University, said Christie's decision made "perfect sense" in light of his sizable lead in the polls. An Aug. 8 Quinnipiac University poll put Christie ahead of his Democratic challenger, State Sen. Barbara Buono of Middlesex County, by 28 percentage points.
"It's a chance to get $12 million in taxpayer dollars to help fund your campaign," Dworkin said, adding that Christie could use any additional funds he raises to sway legislative races or help finance a presidential campaign.
Tuesday's filing shows that Christie, a Republican, has maintained a significant fund-raising edge over Buono.
On Aug. 6, the Buono campaign announced its first filing of $445,000 for the public financing program - just above the $380,000 necessary to qualify and about nine times less than the amount Christie's campaign said it had raised as of Tuesday.
Christie did not participate in the matching funds program in the June primary, for which he raised $6.7 million, according to his campaign.
Campaign spokesman Kevin Roberts said Christie opted into the program for the general election because "it was in the best interest for us in terms of the long-term thinking for the campaign."
Roberts declined to elaborate but said the campaign felt comfortable with the decision, "certainly when it comes to the contrast in terms of fund-raising with our opponent."
Harrison said Christie also may win political points with voters. "Public perception is very important," she said. "People believe in a level playing field."
Christie participated in the program when he first ran for governor in 2009. In that race, he did not receive the maximum state funding until mid-October.
Under the state program, candidates are required to participate in two debates, which have not yet been scheduled. They cannot spend more than $12.2 million each.
Contact Andrew Seidman at 856-779-3846, email@example.com or @AndrewSeidman on Twitter.