Florida Governor Rick Scott, who is a Republican and an NRA member, approved the measure after state lawmakers narrowly backed the move earlier this week.
The influence of the NRA was exemplified in the aftermath of the Sandy Hook shooting during which they strongly opposed the attempt to pass a bill that would involve universal background checks for commercial gun purchasers.
The National Rifle Association (NRA) is suing the State of Florida after Governor Rick Scott, a staunch ally of the firearms lobby, enacted passed a gun control law in the wake of a school shooting that left 17 people dead.
But he said he was still "not persuaded" about the guardian programme.
The measure would raise the minimum age to buy rifles from 18 to 21 and extend a three-day waiting period for handgun purchases to include long guns.
Under caveats to the "guardian" program, teachers who "exclusively perform classroom duties as classroom teachers" won't be allowed to carry guns on campus, unless they have military or law enforcement experience or if they teach a Junior Reserve Officers' Training Corps program.
'We are confident that the courts will vindicate our view that Florida's ban is a blatant violation of the Second Amendment'.
Other provisions would create new mental health programs for schools, establish an anonymous tip line where students and others could report threats to schools, ban bump stocks and improve communication between schools, law enforcement and state agencies. "I mean think about it, you have an enumerated right in the Bill of Rights, there's really no precedent to just do a blanket ban on certain adults", DeSantis said on the show. "Oh my God. Oh my God", the mother said, raising her voice.
But according to the Tampa Bay Times, the state's largest school districts do not seem to be amenable to the idea of arming educators.
Florida's embrace of gun restrictions came as Congress remains mired in partisan divisions on the issue and as other states, from IL to Vermont, consider whether they ought to tighten the rules on gun ownership in the wake of the Parkland attack.
After weighing the matter for two days, Florida Gov. The 19-year-old accused of opening fire at Marjory Stoneman Douglas High School on Valentine's Day was already being held without bond on 17 charges of murder.
Cruz will be arraigned on the 34-count indictment Wednesday.
Cruz's public defender has said he will plead guilty if prosecutors take the death penalty off the table and sentence him to life in prison instead. Bill Nelson (D), Mr. Scott is feeling the same pressure that was brought to bear on the legislature.
Polls suggest voters in Florida want tougher restrictions than the bill offers.
Given Florida's sorry history and Republican control of the legislature, it is not surprising - albeit still disappointing - that lawmakers were unwilling to meet some of the bolder demands of the Parkland students, including a ban on assault weapons and high-capacity magazines. The poll had a margin of error of plus or minus 3.6 percentage points.