Speaking ahead of US President Donald Trump's state visit next week, Bolton said the outcome of the 2016 referendum represented a "triumph of democracy". He also backed Trump's pledge of a trade deal that will be mutually beneficial to the US and Britain, The Age reports.
"We have agonised with you throughout this process," said Bolton. "The US preference is for Britain to follow the course of what the people asked for and leave the EU. It is a lesson for everyone in the triumph of democracy.
As a separate nation again, Britain's impact on the world has the prospect of being even greater."
"And from the US point of view, that is all to the good. I think it will help us... to have another strong and independent country that will help Nato to be more effective, and that has to be a plus."