The experiment took place at the National Ignition Facility at the Lawrence Livermore National Laboratory (LLNL) in California.
LLNL director Dr Kim Budil said: "This is a historic achievement… over the past 60 years thousands of people have contributed to this endeavour and it took real vision to get us here."
Nuclear fusion is described as the "holy grail" of energy production. It is the process that powers the Sun and other stars.
It works by taking pairs of light atoms and forcing them together - this "fusion" releases a lot of energy.
It is the opposite of nuclear fission, where heavy atoms are split apart. Fission is the technology currently used in nuclear power stations, but the process also produces waste that continues to give out radiation for a long time. It can be dangerous and must be stored safely.
Nuclear fusion produces far more energy, and only small amounts of short-lived radioactive waste. And importantly, the process produces no greenhouse gas emissions and therefore does not contribute to climate change.
But one of the challenges is that forcing and keeping the elements together in fusion requires very high temperatures and pressures. Until now, no experiment has managed to produce more energy than the amount put in to make it work.
Dr Melanie Windridge, CEO of Fusion Energy Insights, told the BBC: "Fusion has been exciting scientists since they first figured out what was causing the Sun to shine. These results today really put us on the path to the commercialisation of the technology."
Jeremy Chittenden, professor of plasma physics and co-director of the Centre for Inertial Fusion Studies at Imperial College London, called it "a true breakthrough moment".
"It proves that the long sought-after goal, the 'holy grail' of fusion, can indeed be achieved," he said.
This has been the sentiment echoed by physicists globally, who praised the work of the international science community.
Prof Gianluca Gregori, Professor of Physics at the University of Oxford, said: "Today's success rests upon the work done by many scientists in the US, UK and around the world. With ignition now achieved, not only fusion energy is unlocked, but also a door is opening to new science."
On the question of how long before we could see fusion being used in power stations, Dr Budil, the LLNL director, said there were still significant hurdles but that: "with concerted efforts and investment, a few decades of research on the underlying technologies could put us in a position to build a power plant".
This is progress from when scientists used to say 50-60 years in answer to that question.
One of the main hurdles is getting costs down and scaling up the energy output.
The experiment was only able to produce enough energy to boil about 15-20 kettles and required billions of dollars of investment. And although the experiment got more energy out than the laser put in, this did not include the energy needed to make the lasers work - which was far greater than the amount of energy the hydrogen produced.
Clarification January 9, 2023 : This article was updated to remove that 'a lot' of nuclear waste is produced by Fission. The context around this paragraph was removed pre-publication therefore requiring this clarification.