Speaking before a rally in Missoula, Montana on Thursday, the president praised GIanforte with much crowd approval.
"Any guy who can do a body-slam".
Trump said he originally thought the assault - which took place on the eve of his election - might hurt Gianforte's chances. "Look, I have always been concerned about the President's language on a lot of these things".
Earlier on Thursday, Trump said it "certainly looks" as though Khashoggi is dead, adding that if reports are true that the Saudis killed him, the consequences "will have to be very severe". And he was way up...and I said, 'Oh, this is bad, he's going to lose the election'.
"So this week the president has helped cover up the murder of one journalist and is now praising the assault of another journalist", noted MSNBC's Chris Hayes following Trump's remarks.
Trump called Gianforte a "great guy", a "tough cookie".
The CPJ on Friday demanded an apology from Trump, its advocacy director, Courtney Radsch, said: "We are disturbed once again to see President Trump standing up for those who would attack the press".
"In the aftermath of the murder of Jamal Khashoggi, it runs the risk of inviting other assaults on journalists both here and across the world where they often face far greater threats", The Guardian's us editor, John Mulholland, said in a statement.
Trump's comments come amid an investigation into the presumed murder of journalist Jamal Khashoggi in Saudi Arabia's consulate in Istambul more than two weeks ago. The Guardian has also reacted to the news, noting that the United States president had applauded "the assault of an American journalist".
Some even suggested that Trump's controversial statements, allegedly calling for violence against journalists, might be the reason why the case of the missing journalist of Saudi descent Jamal Khashoggi is not being thoroughly investigated by the US.
While outrage over Trump's remarks erupted on social media.
"In Washington he talks like he's from Montana and he votes like he's Nancy Pelosi", stated President Trump.