"There's nothing to the Russia investigation. It's a waste of time. It's a total and complete farce," Bannon said in an interview on "60 Minutes." "Russian collusion is a farce."
Pressed by CBS's Charlie Rose on whether he believed Russia tried to damage Democratic candidate Hillary Clinton and sway the election in Trump's favor, Bannon said that he has seen the intelligence reports about Russia.
"And are you saying to me those intelligence reports do not suggest that the Russians tried to influence the election?" Rose asked."
"I would never devolve classified information on this show," Bannon answered. "But let me tell you, I think it's far from conclusive that the Russians had any impact on this election."
"Well, that's not the question," Rose responded. "Did they try to influence the American election? That's what the investigation is about.
"We'll have to wait 'til the investigation is finished," Bannon said.
Asked why the President seems to find it hard to criticize the Russians, Bannon disagreed with the characterization.
"He criticizes the Russians all the time," Bannon responded. "He knows the Russians are not good guys. We should be focused on how we bring the Cold War to an end."
Bannon also slammed national security officials in the George W. Bush and Barack Obama administrations who denounced Trump as President.
"This is once again where the narrative is dead wrong," Bannon said, adding that it was the "geniuses" of the Bush administration that helped cause the trade imbalance with China and the US involvement in Iraq.
"That's the geniuses of the Bush administration," Bannon said. "I hold these people in contempt, total and complete contempt."
"They're idiots, and they've gotten us in this situation, and they question a good man like Donald Trump," he added.
Pressed for names, Bannon listed several members of Bush's foreign policy and national security team, including former Vice President Dick Cheney, former Secretaries of State Colin Powell and Condoleezza Rice, and foreign policy adviser Brent Scowcroft.
"By the way, the Obama crowd, almost the same," he added. "Clinton crowd, almost the same. It's three administrations."
Bannon said his one criticism of Trump, whom he still supports, is that he said Trump has believed that changing "personalities" could help him effect his agenda.
"I think if there's one criticism or one observation is that the President in coming here, right, has still thought -- at least in the beginning of his administration -- that it's about personalities and 'If I can change this personality' or 'If I can get this guy on my side, I can do that. And it's not what the institutional logic is."
"I think some of that was with the FBI and others in the State Department and how his foreign policy is playing out," Bannon said. "But I believe you're going to see over time, he's going to have a greater appreciation that this is a city of institutions, and you must engage them as institutions, not just as personalities."
Bannon was ousted in mid-August amid a reshuffling of power within the White House. He has since returned to his role as executive chairman at Breitbart News, a position he held before joining Trump's campaign. Sunday's interview is the first time he has spoken out publicly since his firing.