Chairman Jerry Nadler, D-N.Y., dismissed the White House claim that the conversations between the two were covered by executive privilege, noting Lewandowski had never worked in the executive branch.
After more than five hours of combative questioning, Nadler threatened him with contempt. "You showed the American public in real time that the Trump Administration will do anything and everything in its power to obstruct Congress' work," Nadler said. "Make no mistake, we will hold President Trump accountable."
As the hearing got underway, Nadler also rejected the White House argument made Monday blocking two former senior aides to the president from testifying before the committee at all -- former White House staff secretary Rob Porter and former deputy chief of staff Rick Dearborn -- claiming they had "absolute immunity."
"The White House is intent on preventing the American people from hearing the details, so it is no surprise that the White House blocked two of our witnesses, Mr. Porter and Mr. Dearborn, from showing up at all today," Nadler said.
"I think we should call this what it is, an absolute cover-up by the White House," he said.
The hearing was the first under the committee's new rules Democrats say are designed to facilitate an impeachment inquiry that could lead to articles of impeachment on possible obstruction of justice.
After Lewandowski was sworn in, the hearing took on a circus-like atmosphere as Republicans interrupted with multiple points of order and Democrats did the same.
In his opening statement, Lewandowski told the committee the hearing was a waste of time since he's already testified before Congress three separate times.
"Throughout it all, and to the best of my recollection, I don't recall ever having any conversations with foreign entities -- let alone, any who were offering help to manipulate the outcome of the election," Lewandowski said, praising the president's 2016 victory throughout the statement.
"We as a nation would be better served if elected officials like you concentrated your efforts to combat the true crisis facing out country as opposed to going down rabbit holes like this hearing," Lewandowski said.
Soon after, Trump, aboard Air Force One traveling from New Mexico in California, tweeted, "Such a beautiful Opening Statement by Corey Lewandowski! Thank you Corey! @CLewandowski"
Rep. Hank Johnson, D-Ga., was able to get Lewandowski to confirm some conversations with the president concerning a key point Democrats are pursuing: Trump directing him in the Oval Office, according to the Mueller report, to deliver a message to then-Attorney General Jeff Sessions to limit the scope of Mueller's investigation.
When asked by Johnson why he didn't deliver the message, Lewandowski said he was out of town and at the beach with his kids and denied that he was "squeamish" about delivering it. When asked if the president followed up and pressured him to deliver the message, Lewandowski said that was inaccurate.
The Mueller report says Lewandowski eventually asked former deputy chief of staff Rick Dearborn to deliver the message.
"You chickened out," Johnson said.
"I went on vacation," Lewandowski said, telling Johnson he took his kids to the beach and that his kids were the priority.
Lewandowski, with White House lawyers sitting behind him, repeatedly skirted answering questions by saying, "the White House has directed me not to disclose the subject of any discussions."
He also refused to read the passages from the Mueller report that were in front of him on a committee screen and at one point snapped back at Democratic Rep. Sheila Jackson Lee of Texas, calling her line of questioning a "rant."
He testified that he never thought the president asked him to do anything illegal, saying he disagreed with the premise of Democratic Rep. Steve Cohen's line of questioning asserting it was strange the president would sit down one-on-one and ask Lewandowski to do something illegal.
"I disagree with the premise of your question," he said. "I don't think the president asked me to do anything illegal."
"You got cold feet and you chickened out. The president's trust was misplaced," Cohen, D-Tenn., said about not following through on Trump wanting Lewandowski to deliver a message to Sessions to limit the scope of the Mueller investigation.
Democratic Rep. David Cicilline of Rhode Island took Lewandowski to task for not delivering to Sessions the message dictated to him by President Trump.
"You didn't call Jeff Sessions, you didn't call to meet with him. so the president asked you twice in the Oval Office to deliver a secret message to the attorney general of the United States, right?" Cicilline asked. He called the president's actions "obstruction plain and simple."
Lewandowski referred to the ongoing investigation as the "The greatest crime committed in our generation. Perhaps ever. "
At one point, Nadler said that by Lewandowski not answering questions from the committee he is "proving our point ... the president's intent in obstructing our legitimate oversight. You are aiding him in that obstruction."
And then, in a comment that was met with some gasps in the room, Cicilline urged the committee to hold Lewandowski in contempt of Congress.
As the hearing neared its end, Lewandowksi, over strong GOP objections, was subjected to rapid fire questioning from Democratic counsel Barry Berke in which Berke played a series of media clips of Lewandowski's public statements in an attempt to discredit his testimony and whether he lied to special counsel Robert Mueller.
For example, in an MSNBC interview with Ari Melber from May, Lewandowski said he didn't remember the president asking him to get involved with former Attorney General Sessions or the Department of Justice.
"They have been inaccurate on many occasions and perhaps I was inaccurate that time," Lewandowski said. "I have no obligation to be honest with the media because they are just as dishonest as everybody else."
When pushed on whether he's lied in public statements, he said, "when under oath, I've always told the truth."
Berke then pointed out multiple passages in one of Lewandowski's books in which he told of his private conversations with the president and that he wrote that the Trump had offered him a senior job in the White House around the same time Trump was asking Lewandowski to tell Sessions to restrict Mueller's probe.
Trump's first campaign manager until he was fired in June 2016, Lewandowski has remained close to Trump and others in the West Wing, serving as an outside adviser to Trump since his election but never serving in the White House.
The White House had said Lewandowski could testify only about his time working for Trump on the campaign.
"... Mr. Lewandowski’s conversations with the President and with senior advisers to the President are protected from disclosure by long-settled principles protecting Executive Branch confidentiality interests and, as a result, the White House has directed Mr. Lewandowski not to provide information about such communications beyond the information provided in the portions of the [Mueller] Report that have already been disclosed to the Committee."
Just as Lewandowski testified -- amid reports he might run for U.S. Senate in his home state of New Hampshire -- a new PAC supporting him was registered with the Federal Election Commission. The committee, named Stand with Corey, is not an official campaign committee but is instead an outside political action committee.
Lewandowski himself does not appear to have filed his candidacy with the FEC yet.
The new pro-Lewandowski PAC listed Republican operative Cabell Hobbs as its treasurer, who is also treasures the John Bolton PAC and the John Bolton Super PAC.
Democrat Rep. Hakeem Jeffries of New York began his questioning with a warning to Lewandowski.
"Let me remind you that this is not a Republican primary campaign," Jeffries said. "This is the House Judiciary, you are not on the campaign trail yet."