Trump added that Mattis prefers to build trust with terrorism suspects and reward good behavior.
"I was very impressed by that answer,” Trump told the Times, adding that torture is "not going to make the kind of a difference that a lot of people are thinking."
"I was surprised, because he’s known as being like the toughest guy," Trump continued.
Trump added that Mattis' opinion will not necessarily change his mind on waterboarding.
"If it’s so important to the American people, I would go for it. I would be guided by that. But General Mattis found it to be very less important, much less important than I thought he would say," Trump told the Times.
Trump's comments to the New York Times differ from his remarks on the campaign trail, when he said that the U.S. should "go for waterboarding and tougher than waterboarding."
His selection to lead the CIA, Rep. Mike Pompeo (R-KS) has also defended waterboarding, and Vice President-elect Mike Pence recently would not say whether Trump would bring back waterboarding.
“What I can tell you is that going forward, as he outlined in that famous speech in Ohio, that a President Donald Trump is going to focus on confronting and defeating radical Islamic terrorism as a threat to this country,” Pence told CBS News on Sunday when asked if Trump would bring back waterboarding. “And we’re going to have a president again who will never say what we’ll never do.”
But Trump's support for waterboarding saw fierce pushback from Sen. John McCain (R-AZ) who last week pledged to fight any attempt by Trump to use torture.