Ernst Kohlmann was born in Wesel on 1st June 1926. His father, Martin Kohlmann, had worked as a farmer in South Africa for several years and opened a textile shop in Wesel in the 1920s. His mother, Frieda Kohlmann, née Marx, came from Siegburg. Ernst Kohlmann attended the elementary school in Wesel and, after the family's move to Cologne in 1934, the Municipal Israelite Elementary School in Lützowstrasse, before transferring to the Jewish Realgymnasium Jawne.

On 18th January 1939, he arrived in England with the first Jawne transport led by the Bonn rabbi and Jawne teacher Dr. Rudolf Seligsohn. With some classmates from the Quarta, including Kurt Marx, Julius Weil, Fritz Penas and Hans Walter, he initially lived in the Yavne hostel at 1 Minster Road in the London district of Cricklewood. The Orthodox upbringing that Rabbi Seligsohn sought as head of the house was alien to Ernst, who came from a liberal Jewish home. A few days before the outbreak of the Second World War, the hostel was closed, and the children were distributed among host families outside London. Ernst Kohlmann now lived with various non-Jewish host parents in Bedford.

His parents Martin and Frieda Kohlmann were deported from Cologne on 4th December 1941 and murdered in Riga in July 1944. Ernst's older sister, Margrit Kohlmann (*3.3.1924), survived deportation to Riga and other concentration camps. Shortly before the end of the war, she, and other prisoners of the Stutthof concentration camp, were taken to the Baltic Sea coast by ship. With the few survivors of this death journey, Margrit Kohlmann was liberated by the British Army in Neustadt, Schleswig-Holstein. She married Heinz Behrmann and lived for a time in Hunsrück before emigrating with her husband to Chicago.

Ernst Kohlmann had to leave school in Bedford at the age of 14 and was unable to achieve his wish to attend an art academy. Eventually he found an apprenticeship as a painter and decorator. He anglicised his name and was a member of the Air Training Corps of the R.A.F. from 1942 to 1945. On 8th May 1945, he flew low over his former parental home.
In 1946/47 he worked for the U.S. Army in Germany, where he met his wife Eva, who had also been rescued on a Kindertransport to England. In 1947, Ernest Kolman accepted British citizenship. He set up his own tradesman's business and had two children with his wife. After the children had finished school, Ernest Kolman went to night school to catch up on his A-levels, which he had not been allowed to take as a teenager. Since 1988, he has regularly attended the commemorations of 9th November in his hometown of Wesel and speaks about his story in schools there.

Ernest Kolman now (2016) lives in west London and has five grandchildren, all of whom live in the USA. In June 2016 he became an honorary citizen of his native town, Wesel.