Following the Anschluss (Germany's annexation of Austria) in 1938, he emigrated to London, with limited English and a 16/6d postal order (approximately £32.46 in 2019).

[3] By 1942, he was a political commentator for the BBC and also wrote a weekly newspaper column, coming into contact with General de Gaulle and Tito as a result.

[5] In 1949, Weidenfeld served for a year as the political adviser and Chief of Cabinet to Chaim Weizmann, the first President of Israel.

[6] The city had been divided between Israel and the Hashemite Kingdom of Transjordan after the two sides signed an armistice agreement earlier in the year.

[5] Over the years, the firm published many outstanding titles, including the British edition of Vladimir Nabokov's Lolita in 1959 and Nicolson's biography of his parents, Portrait of a Marriage (1973).

Weidenfeld was also joint chairman of the advisory board of the Blavatnik School of Government in Oxford; adviser to the board of Axel Springer AG Berlin and a columnist for the Berlin newspapers Die Welt, Welt am Sonntag and Bild Zeitung.

Weidenfeld served in many philanthropic capacities including chairman of the Ben Gurion University of the Negev (1996–2004), governor of the Weizmann Institute, vice-chairman of the EU-Israel Forum, member of the founding council of the Rothermere American Institute at the University of Oxford, trustee, Royal Opera House (1974–87) and trustee of the National Portrait Gallery (1988–95).

[15][16] He was appointed Knight Grand Cross of the Order of the British Empire (GBE) in the 2011 New Year Honours for public service.

He was made an honorary senator of Rheinische Friedrich-Wilhelms-Universität, Bonn, in 1996 and awarded the degree of Doctor of Letters, honoris causa, by Oxford University in 2010.