The Legislature agreed to remove a provision that would have made the students eligible for state financial aid, while Christie backed away from his demand that the tuition break not be provided to those who attended a New Jersey high school after 2012.
"This is a compromise that at least makes progress. We've made progress," Sweeney said, surrounded by a group of young undocumented immigrants who call themselves "Dreamers" and have been lobbying for the measure.
Several in the group grew emotional, as did Sen. Teresa Ruiz (D., Essex), the bill's sponsor, who for years has tried to have passed an in-state tuition bill.
"I am overwhelmed with joy," Ruiz said, tears coming to her eyes as she paused to hug Sweeney.
At a news conference after the deal was reached, Christie said he was heartened that a compromise had been put in place that would deliver "tuition equality" to undocumented immigrants.
"These young men and women of our state - whom we have invested hundreds of thousands of dollars in their K-12 education - we're now going to give them an opportunity in an affordable way to be able to continue their education," he said.
Christie said he feared offering financial assistance would turn New Jersey into "a magnet state" for undocumented immigrants in states where it is not available to them and that that could have been costly.
In recent weeks, Christie had come under fire after he promised Hispanic voters that he would support tuition equality while on the campaign trail last month and later appeared to change his stance. Some said they were stunned to hear him say after he was elected to a second term that he would reject the tuition equality bill that was advancing to his desk.
Weeks of finger-pointing followed.
While some linked Christie's apparent backpedaling to his possible presidential aspirations and fear of offending conservatives, he insisted Thursday that wasn't the case.
"Shame on all the people . . . who accused me and others of playing politics with this decision," he said.
But he reiterated his opposition to including state Tuition Aid Grants, saying the undocumented immigrants were not citizens and should not receive "publicly funded tuition aid." These immigrants are not eligible for federal tuition assistance, including Pell grants.
Sweeney, long an advocate of the Dream Act, had accused Christie of flip-flopping and initially said he would make no changes in the bill. Financial assistance had been part of the bill when it was introduced last January.
But Martin Perez, president of the Latino Leadership Alliance of New Jersey and a Christie ally, earlier this month complained that Sweeney was risking losing the chance to pass any tuition equality bill by insisting it include access to financial aid.
Midday Thursday, Sweeney announced that lawmakers had reached a compromise with the governor.
"I'll finally be able to go back to school," said Giancarlo Tello, 23, an undocumented immigrant who was among the group that gathered in the Statehouse.
Tello, the campaign manager for the New Jersey Tuition Equity for Dreamers Coalition, said immigrants like him are often "in the shadows."
Tello, who was brought to the United States from Peru at age 6, added: "It's amazing to think we can lift that veil." While he had pushed for state financial aid, he said he would "begrudgingly accept" its exclusion.
Sweeney said "the quest to make this completely equal" and to restore that provision will continue. "We don't view that in any way at all as being a magnet state - we view that as being a fair state," he said, referring to the governor's objection to including financial aid.
Three of the 15 other states with laws granting tuition equality for undocumented immigrants also offer financial assistance to attend college. The three are Texas, California, and New Mexico.
Tuition equality bills have been debated in the Legislature since 2003.
Parallel efforts in Washington have faltered amid partisan wrangling, as they involve legalizing immigration status. A federal Dream Act would provide a path to citizenship for undocumented immigrants who were brought to the United States as children.
The New Jersey law will become effective immediately, so students will be able to pay in-state tuition starting in January, Sweeney said.
The deal set in motion a complex set of procedural votes. Both chambers had to vote on the bill, which was introduced nearly a year ago, wait for Christie to conditionally veto it and formally propose changes, then vote again.
"After nearly a decade of debate, New Jersey is finally moving beyond the discriminatory policies that for so long have denied a population of young people access to college and the American dream," Sweeney and Ruiz said in a joint statement.
In many cases, tuition will be halved for these immigrants, since they will now qualify for in-state rates, the two senators said.
At his news conference, Christie indicated what led to Thursday's compromise.
"You can have public arguments about a particular piece of legislation or a policy position, and at the same time be having quiet, private conversations where you say, 'How are we going to bring people together to get this done?' " he said.
In return for the removal of the financial aid provision in the bill, Christie said, he agreed to back away from his requirement that a loophole be closed to prevent out-of-state students attending private high schools in New Jersey from receiving in-state tuition.
Sweeney said that the bill also was not changed to render undocumented immigrants after 2012 ineligible for in-state tuition, as Christie had wanted.
The bill says only those who attend a New Jersey high school for at least three years and who graduate in the state or receive the equivalent of a high school diploma can apply for the tuition break.