Ernest Cassutto was born to a secular Jewish family in Probolinggo on the island of Java in the Dutch East Indies (present-day Indonesia), where his father was working as a law professor. They returned to The Netherlands in 1934. During the Nazi occupation of the Netherlands in World War II, family members were hidden in several locations throughout the country. In 1944, Ernest was captured and imprisoned in Rotterdam. His fiancée Hetty was sent to a concentration camp and killed. As the war came to a close, Ernst was rescued by a Christian Dutch member of the underground shortly before he was about to be executed.
After the war, Ernest converted to Christianity and became a minister in the Dutch Reformed Church. In 1952, he emigrated to the USA with his wife and fellow Holocaust survivor, Elisabeth, and their daughter. In 1968, he became the pastor of the Emmanuel Hebrew Christian church in Villa Nova, Baltimore County, where he worked until his retirement in 1979. He published a memoir entitled, The Last Jew of Rotterdam, published in 1974 and later rewritten and updated by his son, Benjamin H. Cassutto.