Karl Koch was born in Darmstadt, Germany in 1897. He was a bank clerk before joining the German Army during the First World War. He was captured by the British army and was held as a prisoner-of-war until October, 1919.

Koch joined the National Socialist German Workers Party (NSDAP) in 1930. Later he became a member of the Schutz Staffeinel (SS). In 1934 Koch became a senior official in Lichtenburg Concentration Camp. Two years later he became the commandant of Sachsenhausen Concentration Camp.

In May 1937, Koch married Ilse Koch, one of the female guards at the camp. Later that year Koch was appointed commandant of Buchenwald, and his wife became a SS-Aufseherin (overseer) at the camp. Known as the "Bitch of Buchenwald" she liked to ride through the camp where she selected prisoners who displeased her to be whipped by Schutz Staffeinel (SS) guards. She also collected lampshades and gloves made from tattooed skins of specially murdered concentration camp inmates.

In September, 1941, Koch was appointed commandant of Majdanek, a Soviet prisoner-of-war camp run by the Waffen SS. In August, 1943, Koch was arrested by the Gestapo and charged with embezzlement and forgery. Found guilty, he was executed in April, 1945.