In stark contrast, Whitaker later refused to answer a question from Democratic Rep. Val Butler Demings of Florida about whether he and Trump had discussed the federal criminal case against Michael Cohen, his longtime former personal attorney and fixer.
He said he was not going to talk about private conversations with the president.
Not long after the hearing got underway -- Whitaker defended his decision to not recuse himself from overseeing Mueller's probe.
"I have not interfered in any way with the special counsel's investigation," Whitaker testified.
Whitaker’s appearance before the committee capped a lengthy standoff with Nadler over the chairman's threat to subpoena the acting attorney general and whether Whitaker might assert that his conversations with the president were covered by executive privilege.
Senior ethics officials in the Justice Department had suggested to Whitaker in December that he should recuse from oversight of the probe in light of previous public statements he made while a private citizen, including an assertion that Mueller’s probe had “gone too far.”
“Why did you ignore the career officials went to extraordinary lengths to tell you that your continued involvement in the special counsel's work would undermine the credibility of the Department of Justice?” Nadler asked in his opening statement.
In spite of his previous criticism of the special counsel’s investigation, Whitaker declined, when asked, to say whether he would characterize it as a “witch hunt” – how President Trump frequently refers to it.
"Congressman, it would be inappropriate for me to discuss an ongoing investigation," Whitaker told Rep. Steve Cohen, D-Tenn.
Asked the same question while testifying before Congress, FBI director Christopher Wray, Deputy Attorney General Rod Rosenstein, and attorney general nominee William Barr all said they did not believe the special counsel is engaged in a “witch hunt.”
Whitaker also fielded questions about the arrest of Roger Stone, the longtime adviser to Trump, who was indicted by special counsel Mueller last month. Congressional Republicans have questioned how heavily-armed armed federal agents took Stone into custody in a pre-dawn raid and have requested FBI director Chris Wray explain the tactics agents used.
“Just know the FBI makes an arrest in the manner most likely to ensure the safety of its agents and of the person being arrested,” Whitaker said, before offering to elaborate on the circumstances considered in Stone’s arrest during a closed session.
Before Whitaker began his testimony, Nadler and the committee's ranking member, Rep. Doug Collins, R-Ga., swapped barbs over the nature of the hearing.
In his opening remarks, Nadler condemned Whitaker for refusing to recuse oversight of special counsel Robert Mueller’s investigation. In an impassioned rebuttal, Collins accused Nadler of attempting “character assassination” and called the hearing “a charade.” Collins then moved to adjourn the hearing before it even began, calling for a roll count vote.
Only hours earlier, it was unclear whether the hearing would even take place, with Whitaker vowing to bail on the session unless Democrats promised not to subpoena him on the same day he would be sitting before Congress for the first time as head of the Justice Department.
Nadler eventually acquiesced, writing Whitaker late Thursday night that he "agreed there is no need to issue a subpoena."
In prepared remarks released prior to his hearing, Whitaker wrote that he would “not disclose” details of his conversations with the president.
"I want to assure you that I will seek to answer the Committee’s questions today, as best as I can,” Whitaker said in the remarks. “But I also must make clear that I will continue the longstanding Executive Branch policy and practice of not disclosing information that may be subject to executive privilege, such as the contents of deliberations or conversations with the President."
Friday's hearing may not be Whitaker's only congressional hurdle. Just hours before Whitaker's testimony, Democrats on another House panel said they had obtained new information that suggests Whitaker failed to pay back money to be distributed to customers of World Patent Marketing, the company he was associated with that had been accused of scamming customers.
Whitaker served on the advisory board of the company charged by the Federal Trade Commission with perpetrating “a scam that has bilked thousands of consumers out of millions of dollars.”