He was born in Vienna in 1897. He studied in Berlin at the Hochschule für die Wissenschaft des Judentums, where he was ordained as a rabbi in 1926. He took rabbinic posts in Bingen, Frankfurt-am-der-Oder and Berlin. He was a disciple of Franz Rosenzweig.

In 1935 he was arrested by the Gestapo, spending six weeks in prison before being released. In 1939 he left Germany on a Kindertransport and went to London, England. His mother and sisters were killed in the Holocaust.

In 1949 he became rabbi of the Edgware and District Reform Synagogue. From 1956 until his retirement in 1963, he lectured in homiletics and theology at Leo Baeck College. He was also active in inter-religious dialogue. His students include Nicholas de Lange.

Maybaum wrote many reflections on Judaism, Christianity, the Holocaust and Zionism. He also wrote on Islam. He is most frequently remembered for his controversial view in The Face of God After Auschwitz (1965) that the suffering of Jews in the Holocaust was vicarious atonement for the sins of the rest of the world. He was connecting the Jewish people to the figure of the "suffering servant" of Isaiah 52 and 53 in the Tanakh (the Christian Old Testament. In the same work he employed Christian imagery, speaking of Auschwitz as the new Golgotha and the gas chambers as replacing the cross.