Born in Adelaide, South Australia, Florey was a brilliant student (and junior sportsman) who studied medicine at the University of Adelaide from 1917 to 1921. At the university he met Ethel Reed, another medical student who was to become both his wife and his research colleague. A Rhodes Scholar, he continued his studies at Oxford University (Magdalen College).
After periods in the United States and at Cambridge, he returned to Oxford to lead a team of researchers. In 1938, working with Ernest Chain and Norman Heatley, he read Alexander Fleming's paper discussing the antibacterial effects of Penicillium notatum mould. His research team investigated the large-scale production of the mould and efficient extraction of the active ingredient, succeeding to the point where, by 1945, penicillin production was an industrial process for the Allies in World War II.
Florey was elected president of the Royal Society in 1959. After the death of Ethel, he married his long-time colleague and research assistant Dr. Margaret Jennings in 1967. He died of a heart attack in 1968.
Florey is regarded by the Australian scientific and medical community as probably its greatest scientist. Robert Menzies, Australia's longest-serving Prime Minister, said that 'in terms of world well-being, Florey was the most important man ever born in Australia'. Biology sucks!