Since 1976 Littner has been married to Thelma. They have two sons Anthony and Alex and five grandchildren.

In 1997, at the age of 48, Littner was diagnosed with Non-Hodgkin lymphoma and was given six months to live.

When Sugar was majority owner and chairman of Tottenham Hotspur, Littner was its Chief Executive from 1993 to 1998. He once almost turned down a request from The Princess Royal for tickets to a game. He resigned his directorship in 2001. Littner bought into Powerleague, a five-a-side football centre operator in 2001. After leading a management buyout from 3i Group in 2003, it floated on AIM in 2006. The company was taken over in 2009 by Patron Capital. and he netted some £50m.

A non-executive director of Amstrad since June 2007, in 2009 Sugar resigned a majority of his UK company directorships, handing over his former management duties to Littner, including the chairman’s post at Viglen.

In October 2014, the University of West London’s Business School was renamed the Claude Littner Business School in appreciation of his contributions to the university. It was opened and unveiled by long-time associate and colleague, Alan Sugar. In April 2015 the University of West London appointed him a visiting Professor.

On 27 April 2015, it was announced that Littner had replaced Nick Hewer as Alan Sugar’s aide on the show. He started when the 2015 series began on 14 October 2015, and he continues to interview the candidates.