Reuben Israel was born in Melbourne, Victoria, in 1894 to Rachel (née Marks) and Abraham (Alfred) Israel. He was educated at Burwood Public School, and later worked as an insurance clerk.
Israel went to South Africa in circa 1913 and at some point joined the Union Defence Force, giving his name as "Gerald Raymond Israel". He fought in West Africa during the early stages of the First World War and, in 1915, volunteered for service in Europe with the South African Overseas Expeditionary Force.
Israel was allotted to the B Company Reinforcements of the 3rd South African Infantry Regiment and sailed for Egypt on board HMT Transylvania, arriving in March 1916. The unit was shortly after sent to France, for service on the Western Front.
Lance Corporal Reuben Israel was killed in action on 16 July 1916 during the Battle of Delville Wood. He is buried in Delville Wood Cemetery, Longueval, Picardie, France.