Donald Trump will be "the disruptor in chief" president, the former head of the CIA has told ITV News.
David Petraeus described the president-elect as "pragmatic", adding that he has "confidence" in the majority of the team he has appointed.
The retired US Army commander, despite being apolitical, was considered by Trump for a role in his top team.
When asked what Trump will be like in office, he told ITV News At Ten's Tom Bradby: "I think this will be a pragmatic individual going forward. He will also, in some respects, be the disruptor in chief.
"And one hopes that the disruption will end up being positive, but there are also other possibilities here as well."
Trump is "in the process of building policies and strategies around campaign slogans" and that there is "a good process underway", Mr Petraeus said.
Speaking from New York, he continued: "All I can go on is my own interaction with him in the fairly long conversation we had when I was privileged to be considered for the position of Secretary of State.
"The further back-and-forth that I had with him, and indeed his close team members, my sense, in a word, is that he is pragmatic."
When asked about the so-called "fake news" dossier, Mr Petraeous added: "Well they of course have been put in front of the current president and the president elect and no one, I don't think, has a firm grip on the credibility of the sources that are involved in this.
"It's going to take a good bit more analysis to determine if there really is credibility to these different assertions and allegations."