Karl Brandt was born in Mühlhausen, Alsace (then in Germany). He became a medical doctor in 1928. He joined the NSDAP in January 1932, and became a member of the SA in 1933. He became a member of the SS in July 1934 and was appointed Untersturmführer. From the summer of 1934 he was Hitler's personal physician. He received regular promotions from the SS and, by January 1943, Brandt was a major general.
In August 1944, Brandt was appointed Reich Commissioner for Sanitation and Health, ranked as the highest Reich authority. He was authorized to issue instructions to the medical organizations of the government, to the party, and the armed forces, in the field of health.
He participated in the euthanasia program beginning in 1939, which involved the systematic execution of the aged, insane, incurably ill, or deformed children by gas or lethal injections in nursing homes, hospitals and asylums. They were regarded as 'useless eaters' and a burden to the German war machine.
On April 16, 1945, he was arrested by the Gestapo, and was condemned to death by a court at Berlin. He was released from arrest by order of Karl Doenitz on May 2, 1945. On May 23, 1945, he was placed under arrest by the British.
Brandt was one of the 15 defendants found guilty of war crimes at the Doctors Trial. He was executed June 2, 1948 at Landsberg prison in Bavaria.