[2] He was educated at Manchester Grammar School, St Paul's and Corpus Christi College, Cambridge.
[citation needed] Starting work for the family company in Hammersmith, London in 1935, Sieff first visited Mandatory Palestine in 1939.
He joined the Royal Artillery in the British Army at the outbreak of World War II and received an OBE in 1944 for gallant service.
[3] Exiting the British Army with the rank of colonel, he returned to Marks & Spencer, but was asked in 1948 by the first Prime Minister of Israel, David Ben-Gurion, to become an adviser on transportation and supplies to the Israeli Defence ministry.
Sieff joined the Israel Defense Forces and helped co-ordinate Marks & Spencer goods and finances to support the new state.