Trump declared that an "eight-year assault" on gun ownership rights had come to a "crashing end" with his election.
He vowed to press forward on his plan to construct a border wall, despite setbacks in securing funding for the project or convincing Mexico to pay for it.
And after regaling the crowd with a retelling of his Election Night victory, he revived a campaign trail insult of Sen. Elizabeth Warren, who he suggested was plotting to challenge him in 2020.
Even amid the right-wing rhetoric, however, Trump warned that simply electing him president wouldn't suffice in advancing the hard-right agenda his audience hopes to see realized.
"We can't be complacent," Trump said. "These are dangerous times. These are horrible times for certain, obvious reasons. But we are going to make them great times again."
It was a moment of darkness in what was otherwise a valedictory speech to an organization that backed Trump early and eagerly. Trump lavished the organization and its leaders, including executive vice president Wayne LaPierre, with praise in his remarks, and vowed to uphold his promises.
"You have a true friend and champion in the White House. No longer will federal agencies be coming after law-abiding gun owners," Trump said in his speech. "No longer will the government be trying to undermine your rights and your freedoms as Americans. Instead, we will work with you, by your side."
While Trump, as well as his fellow speakers at the NRA meeting, decried Obama for his stance on guns, sales of firearms in over the past eight years surged, large due to fears that Obama would implement tougher gun control laws.
Persistent efforts to put in place new restrictions on gun sales, however, largely failed in Congress, even after repeated mass shootings. Obama had called the inability to pass meaningful gun control as one of the greatest disappointments of his presidency. Instead, he signed dozens of executive orders and memorandums putting in place new rules on background checks and sales.
His address Friday amounted to a return for Trump to the type of staunchly conservative setting that he used as a candidate to appeal to Republican voters. It's the first time a sitting US president has spoken at an annual meeting of the NRA since Ronald Reagan addressed the group in 1983.
Trump reaffirmed his campaign pledges to expand gun ownership rights and roll back some of the restrictions instituted under his Democratic predecessor. But made no new policy pronouncements to the gathering, which is taking place at a downtown convention center here.
Instead, he used the speech to boast about his win and warn potential rivals against challenging him.
"Only one candidate in the general election came to speak to you, and that candidate is now the president of the United States, standing before you, again," Trump said. "I have a feeling that in the next election, you're going to be swamped with candidates, but you're not going to be wasting your time."
"You'll have plenty of those Democrats coming over, and you're going to say, no sir, no thank you. No ma'am, perhaps ma'am," he said, going on to make a racially charged jab at Warren.
"It may be Pocahontas, remember that," Trump said. "She is not big for the NRA, that I can tell you. But you came through for me, and I am going to come through for you."
Trump is under pressure to demonstrate wins on the set of conservative principles he laid out as a candidate. In the past month, he's made about-faces on issues like China, trade and NATO, leading to some conservative angst the reversals reflect a drift away from the underpinnings of his campaign.
At Autrey's Armory, an indoor shooting range 40 minutes south of downtown Atlanta, patrons said they regarded Trump favorably as he nears 100 days in office. But they worried his record on gun rights would be hampered by Congress.
"I think it's going to be a mixed bag," said Mike Holtzclaw, a municipal public safety official in Atlanta who owns guns for hobby and self-protection. "I think that some gun owners are going to feel that he's done the best that he can, and I really think he's doing the best that he can. But I think some will be disappointed."
"That's going to be true not just of gun ownership," he said. "That's going to be true of several of the things that he's trying to put forward."
In his remarks, Trump reinforced one pledge that's so far been unfulfilled: building a border wall in an bid to halt illegal immigration. He repeatedly declared the country needed the physical barrier to keep Americans safe.
"We will build the wall, no matter how long this number gets, or how high this gets. Don't even think about it. Don't even think about it," Trump said. "You know, they're trying to use the number against us, because we've done so unbelievably at the borders already; they are trying to use it against us. But you need that wall to stop the human trafficking, to stop the drugs, to stop the wrong people. You need the wall."
Since taking office, Trump has barely mentioned gun ownership rights outside a few scattered mentions during the campaign rallies he's already holding for his reelection bid. He has taken steps to roll back certain Obama-era restrictions on gun use and sales, but has not yet made a concerted effort to relax current gun laws.
Advocates say they are looking for Trump to help advance legislation making concealed-carry permits valid across state lines, as well as a measure that would loosen requirements for buying gun silencers.
In February, Trump signed a measure that reversed a rule barring gun sales to certain mentally ill people, which was written as a response to the 2012 elementary school shooting in Connecticut. His administration also rolled back a regulation banning lead ammunition on wildlife refuges that was implemented on the last full day of the Obama presidency. But Trump himself didn't announce the change, leaving the task instead to his Interior secretary.
But Trump's chief accomplishment, in gun advocates' view, was his successful nomination of Neil Gorsuch to the Supreme Court, which returned a conservative majority to the panel and opened the door for legal challenges to some restrictive gun laws in states around the country. The NRA has already launched legal actions against an assault weapons ban in California in the hopes it will be eventually overturned by the high court.
As a candidate, Trump's pledge to appoint conservative judges earned him early backing from the NRA, which threw its support behind the Republican in May of last year after he spoke at their meetings in Louisville.
Trump's enthusiastic embrace of the guns rights organization sometimes appeared discordant: The President was once a proponent for stricter gun control laws, and hails from a city with some of the toughest restrictions on firearms in the country.
Trump's two sons, both avid hunters, worked to connect their father to gun rights advocates and act as credible voices for him on the subject, but he found himself overstepping occasionally in his rhetoric.
When Trump suggested that a shooting at a gay nightclub in Orlando could have been prevented if the victims were armed, the NRA offered a rare rebuke, saying his remark "defies common sense." Trump later offered clarification.
However, when Trump suggested that "Second Amendment people" take matters into their own hands should Clinton be elected, the NRA backed Trump, saying he was right that Clinton was a threat to their constitutional right to bear arms.
As traditional Republican groups either abandoned Trump on the campaign trail last year, or remained quiet in their support of the brash and controversial candidate, the NRA loudly proclaimed its support and poured millions of dollars into pro-Trump advertising.
The gun organization spent heavily in states where its membership overlapped with the white working-class voters Trump was targeting, including in Pennsylvania and Ohio. Their spending far outpaced previous election cycles, when the Republican candidates voiced more moderate stances on gun control.
On Thursday, the NRA said it was money well spent.
"We are very pleased," said Jennifer Baker, an NRA spokeswoman. "He ran as one of the most unabashed pro-second amendment candidates in my lifetime, and he really has kept his promises and done a lot for people who care about the Second Amendment and the Constitution in his first 100 days."