Answering questions before the House judiciary committee, Lewandowski, Trump's former campaign manager, said he did not relay a message to Sessions -- which was detailed in the second volume of special counsel Robert Mueller's report -- because he was on vacation with his children.
According to the report, the message stated that Sessions should publicly announce that the Russia investigation was "very unfair" to Trump.
Rep. Steve Cohen, D-Tenn., asked whether Lewandowski found it strange that the president would "sit down with you one-on-one and ask you to do something that you knew was against the law?"
Lewandowski responded that he didn't believe he was asked to break the law.
"I didn't think the president asked me to do anything illegal," he said.
Democratic committee lawyer Barry H. Berke also pressed Lewandowski about whether he lied in an interview earlier this year in which he said he couldn't recall any conversation he had with Trump about Sessions.
"I have no obligation to have a candid conversation with the media whatsoever, just like they have no obligation to cover me honestly and they do it inaccurately all the time," Lewandowski said.
When asked if he was admitting to lying during the interview Lewandowski said the media "have been inaccurate on many occasions and perhaps I was inaccurate that time."
In opening remarks before the committee Lewandowski said he doesn't recall having conversations with foreign entities nor did he collude with foreign attempts to interfere in the 2016 U.S. election.
He answered questions from the committee related to the Mueller investigation weeks after receiving a subpoena from the panel.
"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," he said in his opening statement.
"As I have said publicly many times, anyone who attempted to illegally impact the outcome of an election should spend the rest of their life in jail."
His opening statement didn't mention allegations of obstruction of justice.
Early in his testimony, Lewandowski repeatedly refused to answer questions, citing instruction from the White House not to disclose White House discussions. He said it wasn't his idea to invoke executive privilege during the hearing, citing a letter from White House counsel Pat Cipollone seeking to restrict Lewandowski's testimony.
Because Lewandowski is a private citizen, he was accompanied Tuesday by a White House attorney.
Committee Chairman Jerry Nadler called Cipollone's claims about executive privilege "shocking and dangerous."
"The president would have us believe that he can willfully engage in criminal activity and prevent witnesses from testifying before Congress -- even if they did not actually work for him or his administration," Nadler said in a statement. "If he were to prevail in this cover-up while the judiciary committee is considering whether to recommend articles of impeachment, he would upend the separation of powers as envisioned by our founders. No one is above the law."
Lewandowski's name appears about 100 times in the second volume of the Mueller report. Mueller said there wasn't sufficient evidence to prove Trump obstructed justice by interfering in the probe, but did not clear him, either. The report listed several "episodes" it said were potential obstructions.
Lewandowski appeared before the House intelligence committee last year, but refused to answer questions.
Other witnesses listed to testify Tuesday were former campaign adviser Rick Dearborn and former White House staff secretary Robert Porter.