Yet the law, the biggest educational achievement of Christie's term, retains something that the Republican governor has long railed against - seniority.
The "last in, first out" system - held sacred by virtually every union - is derided by Christie because it prevents experienced educators from being laid off before newer, possibly more innovative, teachers.
Christie's inability to change the seniority system underscores the fact that even as he has built his image nationally and locally as a hard-charging change agent on educational issues, he has yet to rack up some critical victories.
In 2011, which Christie declared the "year of education reform," he failed to check off key items on his to-do list: create a merit-based teacher compensation system, empower principals to make hiring decisions, and launch a voucher system so students in failing schools can matriculate elsewhere. In addition, his attempt to revamp the state's formula for funding schools was rejected by the state Supreme Court, which ordered more money for urban districts.
Christie did not say Monday whether eliminating seniority rules would be a focus going forward, but he described the tenure bill as a start.
"One thing that this job teaches you . . . is patience," Christie said.
He indicated that negotiations over tenure reform, which involved New Jersey Education Association leaders and his education commissioner, could represent a thaw in the administration's frosty relationship with public educators.
"Now that we've had the experience of being able to negotiate with each other and realize that we're not just going to do it for headlines, and that we're actually going to get something done . . . I think that distrust has broken down to a certain extent," he said.
Those headlines are legion. In 2010, a Bergen County union official wrote a memo that included a joke in which the governor's death figured in the punchline; the NJEA refused to fire him, as Christie demanded. This year, Christie and NJEA executive director Vincent Giordano called on each other to resign. Both refused. Giordano was in the audience Monday, chuckling at Christie's quips.
The NJEA spent millions on anti-Christie ads after he cut money to schools, while Christie has made the NJEA his punching bag, accusing it of engaging in "political thuggery" and not caring about children. He regularly cites NJEA leaders' salaries and alleged fancy offices and luxury cars.
On Monday, Christie actually thanked the NJEA for its work on the bill. But it was unclear if he can wrest its support for his other proposals. The NJEA is the state's biggest donor to legislative candidates, making its opposition to any bill a high hurdle.
"We're certainly glad to have a seat at the table. . . . We hope to be able to continue that relationship," said Barbara Keshishian, the group's president.
She hoped the tenure law was "a step in the right direction," but did not indicate a warming to Christie's other plans. "We're willing to sit down and have discussions about any of the issues that are on the table," she said.
From Iowa to California to Harvard's school of education, Christie has traveled the country and spoken emotionally about the need to save poor children in failing urban schools, recounting - as he did again Monday - that his parents moved from Newark to Livingston for better schools.
That has burnished Christie's reputation as a Republican comfortable talking about urban issues, and he can claim some successes.
He expanded charter schools, though the state was moving in that direction before he got into office. A school-choice program that started before his term, which allows students in limited locales to switch districts, also has grown. And Christie started a teacher-evaluation program that will become part of the new tenure system.
Last year, Christie signed the Urban Hope Act, which could put nearly 40 percent of Camden's public school children into privately run schools.
That is a limited pilot program, however, and less dramatic than the Opportunity Scholarship Act, which would give tax breaks to companies that pay for students in failing districts to attend elsewhere. That bill has stagnated in the union-friendly Assembly.
Angel Cordero, a school-choice advocate who runs an alternative school in Camden and was a Christie appointee to a state education task force, said he was "frustrated about the slow pace" change.
He believes the Opportunity Scholarship Act can immediately save thousands of minority children, but it was displaced by the Urban Hope Act bill last year and tenure reform this year.
Other advocates are optimistic.
Christie has turned the system around "180 degrees," said Derrell Bradford of the group Better Education for Kids, which supports the governor's education agenda.
Before, "there was only one conversation you could have about education in New Jersey, and that was about more funding," he said. Now, conversations are being held about educational "access for kids regardless of their income, skin color, or zip code, what is essentially a sweeping overhaul."
"Sure, there are five or six other things we want to get done. . . . But the things that have gotten done are tremendous, especially when you consider where we were," Bradford said.
"Our work is far from done," state education commissioner Chris Cerf said Monday, in remarks before Christie spoke.
He described seniority protections for teachers as immoral and said: "This is a great tenure-only bill, but it does nothing to address crucial issues affecting our school."
Keshishian, the union president, will have a lot to say about those issues. Christie shook her hand as he left the bill-signing. Asked when that had last happened, she paused for a few moments.
Contact Matt Katz at 609-217-8355, firstname.lastname@example.org, or follow on Twitter @mattkatz00. Read his blog, "Christie Chronicles," at www.philly.com/ChristieChronicles.