Corbyn, who said in 2014 he wished Nato “didn’t exist”, also told the Radio 2 show that the transatlantic military alliance was “a Cold War product” that led to a “deepening” of tensions.
“As we all know it was set up it after the Second World War,” he said. “It actually developed from the Atlantic Charter, and the whole thing was a tit-for-tat between the [Communist] Warsaw Pact and Nato.
“And that led to the deepening of the Cold War. Nato still exists, we will be members of it, and I will be a voice that I hope will be going to de-escalate tensions and improve dialogue.”
Corbyn insisted Labour’s manifesto was committed to staying in Nato but it would play a “constructive role”.
“We cannot go into a world where we are promoting tensions when the real insecurities in the world actually come from cyber attacks, from terrorism and of course from the cases of climate change and global warming, which does affect so many people all around our planet.”
Earlier, he told ITV’s This Morning he was “very sorry” for “everything that has happened” in his party regarding anti-Semitism.
The Labour leader came under fire after he refused four times to say sorry during an interview with the BBC’s Andrew Neil last week.
Corbyn said: “Our party and me do not accept anti-Semitism in any form. […] Obviously I’m very sorry for everything that has happened.
“But I want to make this very clear: I am dealing with it. I have dealt with it. Other parties are also affected by anti-Semitism.”