"Brexit is going to end up being a great thing," Trump told The Times of London. Extracts of the interview are being published ahead of its full release.
Speaking with former UK Justice Secretary Michael Gove, Trump praised the UK as being "so smart in getting out."
US President Barack Obama had said the UK would end up "at the back of the queue" if it left the EU when it came to American trade deals, but Trump appeared to reverse this position.
"We're going to work very hard to get it done quickly and done properly," he told Gove. "Good for both sides."
Trump, who campaigned himself on tough — some would say hateful — immigration policies. said he expected other countries to follow the UK's lead.
"Countries want their own identity and the UK wanted its own identity, but I do think if they hadn't been forced to take in all of the refugees than you wouldn't have a Brexit," he told Gove.
He also criticized German Chancellor Angela Merkel's open door immigration policies, which saw roughly 1 million refugees enter Germany in 2015. "I think she made one very catastrophic mistake and that was taking all of these illegals," he said, the Times released over Twitter.
According to Trump, the EU the UK just left was "basically a vehicle for Germany," he said, the BBC reports.
However, Merkel is "by far the most important European leader," the incoming US president said, and he intends to begin his term "trusting" both her and Russian President Vladimir Putin, who he has been accused of having unethical ties to.
He implied the trust might not last long.
Trump also urged the UK to veto any new UN Security Council resolutions critical of Israel.
Ahead of his inauguration in the next week, Trump spoke with The Times and the German newspaper Bild.
