"He's had a lot of of credibility problems," Trump told The Daily Caller in an an interview about Woodward's book, "Fear: Trump in the White House."
"I probably would have preferred to speak with him, but maybe not. I think it probably wouldn't have made a difference in the book. He wanted to write the book a certain way," the president said.
"It's just nasty stuff," Trump said of the scathing details in Woodward's tome, which the president suggested might be from "disgruntled employees or just made up" by the reporter.
The forthcoming expose says that Trump referred to Attorney General Jeff Sessions as a "traitor," and "mentally retarded," while himself being called an "idiot" by White House chief of staff John Kelly in discussions with associates.
The Washington Post, published an article detailing those and other highlights of the book, which include claims that Trump administration officials snatched documents off of the president's desk to avoid having him sign them, that Trump compared his first chief of staff, Reince Priebus, to "a little rat," and called for the assassination of Syria's leader.
The article said Woodward's book "reveals a 'nervous breakdown' of Trump's presidency."
In a late-night Tuesday Twitter post, Trump pushed back against the reporting about the alleged comments on Sessions.
Donald Trump tweet: The already discredited Woodward book, so many lies and phony sources, has me calling Jeff Sessions "mentally retarded" and "a dumb southerner." I said NEITHER, never used those terms on anyone, including Jeff, and being a southerner is a GREAT thing. He made this up to divide!
Woodward, who first gained famed for his reporting with Washington Post colleague Carl Bernstein on the Watergate scandal that ended the presidency of Richard Nixon, told Trump in a call last month that he had repeatedly sought an interview with Trump but received no response from the president's aides. Trump told Woodward he would have "loved" to speak to him for the book.
White House Press Secretary Sarah Huckabee Sanders, in a statement, said, "This book is nothing more than fabricated stories, many by former disgruntled employees, told to make the President look bad."
Kelly issued a statement of his own denying that "I ever called the President an idiot."
Kelly is quoted in the book as saying of Trump, "It's pointless to try to convince him of anything. He's gone off the rails. We're in Crazytown. I don't even know why any of us are here. This is the worst job I've ever had."
John Dowd, Trump's former lawyer, on Tuesday denied to Axios that he had believed that the president was a "f---ing liar," as Woodward's book claims.
Defense Secretary Jim Mattis also denied saying the quotes attributed to him, referring to them as "a product of someone's rich imagination."
In the highlights published by the Post, Mattis is described as frustrated with the president, likening his understanding to that of a "fifth- or sixth-grader."
Woodward told The Post on Tuesday that he stood by his reporting.
Both Kelly's denial and Sanders' broadside against the Woodward book were released with a list of more than 50 "accomplishments" that the Trump administration says it has achieved since early 2017.
The final item on that list reads "We have begun BUILDING THE WALL. Republicans want STRONG BORDERS and NO CRIME. Democrats want OPEN BORDERS which equals MASSIVE CRIME."
Other accomplishments included: "Cancelled the illegal, anti-coal, so-called Clean Power Plan;" "Obamacare individual mandate penalty GONE;" "Helped win U.S.-Mexico-Canada's united bid for 2026 World Cup;" and "Withdrew the United States from the job-killing Paris Climate Accord."
In the Aug. 14 phone call between Woodward and Trump, a transcript and recording of which The Post published online Tuesday, Trump complained that "I have another bad book coming out."
"Big deal," Trump added.
He also told Woodward in the 11-minute call that the book would not be accurate, because Trump himself had not been interviewed. Woodward said he had sought a sit-down with Trump through about a half-dozen people, including senior advisor to the president Kellyanne Conway. Trump said he "would've loved" to talk to Woodward, but never received the invites.
"So we're going to have a very inaccurate book, and that's too bad. But I don't blame you entirely," Trump said.
Simon & Schuster, the book's publisher, did not immediately reply to CNBC's request for a statement in response to the White House.
Trump in 2013 had implicitly endorsed Woodward's reporting when it was focused on the administration of President Barack Obama.
The full statement by Sanders:
"This book is nothing more than fabricated stories, many by former disgruntled employees, told to make the President look bad. While it is not always pretty, and rare that the press actually covers it, President Trump has broken through the bureaucratic process to deliver unprecedented successes for the American people."
"Sometimes it is unconventional, but he always gets results. Democrats and their allies in the media understand the President's policies are working and with success like this, no one can beat him in 2020 – not even close."
Kelly's full statement:
"The idea I ever called the President an idiot is not true. As I stated back in May and still firmly stand behind: "I spend more time with the President than anyone else, and we have an incredibly candid and strong relationship. He always knows where I stand, and he and I both know this story is total BS. I'm committed to the President, his agenda, and our country. This is another pathetic attempt to smear people close to President Trump and distract from the administration's many successes."
Mattis' full statement:
"The contemptuous words about the President attributed to me in Woodward's book were never uttered by me or in my presence. While I generally enjoy reading fiction, this is a uniquely Washington brand of literature, and his anonymous sources do not lend credibility.
While responsible policy making in the real world is inherently messy, it is also essential that we challenge every assumption to find the best option. I embrace such debate and the open competition of ideas. In just over a year, these robust discussions and deliberations have yielded significant results, including the near annihilation of the ISIS caliphate, unprecedented burden sharing by our NATO allies, the repatriation of U.S. service member remains from North Korea, and the improved readiness of our armed forces. Our defense policies have also enjoyed overwhelming bipartisan support in Congress.
In serving in this administration, the idea that I would show contempt for the elected Commander-in-Chief, President Trump, or tolerate disrespect to the office of the President from within our Department of Defense, is a product of someone's rich imagination."