The public testimony can be viewed below, live as it happens on NBC News' live stream.
As expected, tensions were high throughout the almost six-hour hearing.
Rep. Doug Collins (R-Ga.), the ranking member of the House Judiciary Committee, questioned acting Attorney General Matthew Whitaker about the baseless claim that CNN might have been tipped off to the arrest of Roger Stone, a longtime associate and informal adviser to President Donald Trump.
The committee's Democratic leadership and Mr Whitaker's team sparred on Thursday night over whether Mr Whitaker would even turn up for the hearing.
"You decided that your private interest in overseeing this particular investigation, and perhaps others from which you should have been recused, was more important than the integrity of the department", said Nadler, of NY.
Its likely too early to discern the implications of these revelations. "You've only got five days left on the job". The Senate is expected to vote as soon as next week on confirming William Barr, Trump's pick for attorney general. House Democrats also berated Whitaker on the administration's immigration policy and about family separations at the border.
The majority of Friday's questioning surrounded Whitaker's oversight of special counsel Robert Mueller's Russian Federation investigation.
After Mr Whitaker, the former chief of staff to Mr Sessions, was temporarily appointed to the position, it emerged he had written several op-eds that were sharply critical of Mr Mueller's probe.
"You have challenged my character", Whitaker began to say after Raskin repeatedly asked for the name of the charity the acting attorney general had previously run.
Until Friday, it was not clear-cut how this power would explicitly manifest itself.
The hearing briefly went off the rails, with some in attendance jeering at Whitaker for the gutsy move.
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However, all Russian efforts were ignored or blocked by the United States, the senior diplomat said. The 60 days were up at the beginning of February.
"And so I think he really didn't know what to do, so he tried to be dismissive", she added.
Nadler cracked a smile, but he was unfazed.
Whitaker then said he would not answer questions based on representatives' "speculation".
Democrats have expressed concerns about Whitaker's previous partisan statements about the Mueller probe, his resumé and not being in the line of succession to succeed Jeff Sessions.
"It's shocking how nervous and unsure of himself Whitaker appears to be", Renato Mariotti, a former federal prosecutor, wrote in an e-mail to TIME.
On Thursday the committee clashed with the Department of Justice over Democrats' plans to subpoena Whitaker - during the hearing if Nadler chose to do so.
There were other ways that Democrats' power was on display. He called for an adjournment, a motion that was easily defeated.
The hours preceding the actual hearings had all the hallmarks of the drama political observers predicted in the battle between the White House and the Democratic-controlled House that will define the next two years.
House Judiciary Committee Chairman Rep. But Whitaker fired back, saying through a letter from the Justice Department that he would not testify at all if the committee issued a subpoena.
But on Friday, before concluding the hearing, Nadler made clear that option was still on the table.
"I'm proud of my passion, Mr. Whitaker", she tweeted. It's not unusual for committee chairs to interrupt long-winded answers, or for members to remind their political opponents when they stretch the clock to get more television time.