Leonard was born in Germany on 7 April 1935 to a family of cattle dealers. My Voice: Leonard Kaufmann recounts the story of his life before, during and after the Holocaust. Leonard arrived in London on the Kindertransport, thanks to his uncle arranging with a couple that they would pay the 50 to sponsor his entry to England. The Argles sponsored 30 children in total, and Leonard lived in their home in Staffordshire with them almost until the end of the war. Tragically, his parents and siblings all perished in the Holocaust.

Following time in hostels, Leonard did National Service in Hong Kong. On his return, he met Ruth and they married in 1961 and moved into a house in Gatley, Manchester where they lived for 40 years and had two daughters, Sarah and Debra. Leonard worked for his uncle's business and as a clothing manufacturer, and later spent many years as the administrator for the Yeshurun Synagogue.