A handgun from a collection of illegal guns is reviewed during a gun buyback event in Brooklyn, New York. File
The 6-3 decision strikes down a more than century-old New York law that required a person to prove they had a legitimate self-defense need, or "proper cause," to receive a permit to carry a handgun outside the home.
Several other states, including California, have similar laws — and the court's ruling will curb their ability to restrict people from carrying guns in public.
Democratic President Joe Biden denounced the decision, saying it "contradicts both common sense and the Constitution, and should deeply trouble us all."
"We must do more as a society — not less — to protect our fellow Americans," Biden said. "I call on Americans across the country to make their voices heard on gun safety."
Despite a growing call for limits on firearms after two horrific mass shootings in May, the court sided with advocates who said the US Constitution guarantees the right to own and carry guns.
The ruling is the first by the court in a major Second Amendment case in over a decade, when it ruled in 2008 that Americans have a right to keep a gun at home for self-defense.
It was a stunning victory for the National Rifle Association lobby group, which brought the case along with two New York men who had been denied gun permits.
"Today's ruling is a watershed win for good men and women all across America and is the result of a decades-long fight the NRA has led," NRA executive vice president Wayne LaPierre said in a statement.
"The right to self-defense and to defend your family and loved ones should not end at your home."
New York Governor Kathy Hochul called it a "dark day," while California's leader Gavin Newsom termed the decision "shameful."
"It is outrageous that at a moment of national reckoning on gun violence, the Supreme Court has recklessly struck down a New York law that limits those who can carry concealed weapons," Hochul said.
"This is a dangerous decision from a court hell bent on pushing a radical ideological agenda and infringing on the rights of states to protect our citizens from being gunned down in our streets, schools, and churches," Newsom tweeted.
Justice Clarence Thomas wrote the majority opinion and was joined by the other five conservatives on the nine-member court, three of whom were nominated by former Republican president Donald Trump.
Thomas said the New York law prevents "law-abiding citizens with ordinary self-defense needs from exercising their Second Amendment right to keep and bear arms in public for self-defence." "We conclude that the State's licensing regime violates the Constitution," Thomas said.
The ruling comes as the US Senate is considering a rare bipartisan bill that includes modest gun control measures.
Democratic Senator Dick Durbin said the ruling "makes it all the more important for Congress to take actionable steps to protect our kids and communities from this nation's gun violence epidemic.
"In a nation of almost 400 million firearms, this Supreme Court decision is an invitation for more gun deaths and chaos in America's neighborhoods," he said.
On May 14, an 18-year-old used an AR-15-type assault rifle to kill 10 African Americans at a supermarket in Buffalo, New York.
Less than two weeks later 19 children and two teachers were shot and killed at an elementary school in Uvalde, Texas, by another teen with the same type of high-powered, semi-automatic rifle.
In the decision, Justice Samuel Alito dismissed arguments that guns outside of homes lead to great violence, including when it comes to mass shootings.
"Why, for example, does the dissent think it is relevant to recount the mass shootings that have occurred in recent years?," he wrote.
The New York law said that to be given a permit to carry a firearm outside the home, a gun owner must clearly demonstrate that it is explicitly needed for self-defense.
Gun-rights advocates said that violated the Second Amendment of the Constitution, which says "the right of people to keep and bear arms shall not be infringed."
The three liberal justices on the Supreme Court dissented from the ruling. "Many states have tried to address some of the dangers of gun violence," Justice Stephen Breyer said.
"The Court today severely burdens states' efforts to do so." More than half of US states already allow permitless carry of firearms, most of them only doing so in the past decade.
The New York state law dated to 1913 and had stood based on the understanding that individual states had the right to regulate gun usage and ownership.
Over the past two decades more than 200 million guns have hit the US market, led by assault rifles and personal handguns, feeding a surge in murders, mass shootings and suicides.Agence France-Presse