Karl Landsteiner was born on June 14, 1868, in Vienna, Austria. In 1891, he earned a medical degree from the University of Vienna. After spending five years in various laboratories in Munich conducting research, Landsteiner returned to Vienna. Landsteiner became an assistant under Max von Gruber in the Hygiene Institute in Vienna in 1896. From 1898 to 1908, he became an assistant in the University Department of Pathological Anatomy in Vienna. It was there that Landsteiner began his studies on morbid physiology. In 1908, he was appointed Prosector in the Wilhelminaspital in Vienna. By 1911, he became Professor of Pathology at the University of Vienna.
Following World War I, he left for the Netherlands. In 1919, Landsteiner accepted the position of Prosector to a Roman Catholic Hospital at The Hague. In 1922 he joined the Rockefeller Institute for Medical Research in New York, and remained there for the remainder of his life. In 1939, he was granted Emeritus Professor at the Rockafeller Institute, but continued his research in the laboratories. During this period he became an American citizen.
Much of his research focused around morbid anatomy and immunology. He revealed new information regarding the immunology of syphilis and named the immunological factors haptens. Landsteiner also laid the foundations for the cause and immunology of poliomyelitis.
In 1901-1903, Landsteiner discovered that during a blood transfusion from human to human, different foreign bloods tends to clump and cause shock or jaundice. During this research, he proposed that the paternity of a child can be determined because the characteristics of blood groups are inherited. In 1909, Landsteiner categorized the modern system for human bloods into A, B, AB, and O groups. Landsteiner, along with A. S. Weiner, identified the Rh factor in 1940.
In 1930, Landsteiner received the Nobel Prize for Medicine for his work on differentiating the blood groups.
Landsteiner died on June 26, 1943, of a heart attack while still working at his laboratory in New York.