McAlpine was not present at London's High Court as the solicitors for both broadcasters apologised unreservedly and confirmed the payment of damages and substantial costs.
The baron was the unnamed subject of a controversial BBC Newsnight documentary which wrongly suggested that he had abused children at a home in North Wales.
After the show aired, McAlpine's name circulated on Twitter, before it emerged that former Bryn Estyn resident Steve Messham had wrongly identified the Tory peer.
McAlpine later released a statement reserving the right to sue those who had defamed him.
He also threatened legal action against ITV after Phillip Schofield brandished a list of alleged paedophiles with Conservative party links in front of Prime Minister David Cameron on This Morning.
These include wife of the speaker of the House of Commons Sally Bercow and The Guardian columnist George Monbiot.