Lejb was born on 3rd May 1921 in Poland to Herschel and Chaya-Rachel. His family were Zionist and Hebrew speakers. Lebj attended the Tarbut school in Ludmir followed by an agricultural school. He joined the Gordonia youth movement and in 1938 his father sent him to Israel to continue his studies in the agricultural youth village of Ben Shemen.

He enlisted in the RAF and for three years he served mainly in Egypt and Italy. On 29 July 1944, there was an accidental explosion at an airfield in Egypt in which Lejb died from injuries sustained.

He was laid to rest at the Heliopolis British Military Cemetery in Cairo. His family in Poland were killed in the Holocaust.