Chain, born the son of a chemist in Berlin, Germany, graduated in 1930 from the Friedrich-Wilhelm University with a degree in chemistry. He left Germany for England in 1933 and, after two years' research at Cambridge University, joined Howard Florey at Oxford. Here his brilliance as a biochemist was put to good use in the difficult isolation and purification of penicillin – work that Alexander Fleming had been unable to carry out. He shared the 1945 Nobel Prize for physiology or medicine with Florey and Fleming for this achievement.

After 1945 he was professor of biochemistry at the Superior Institute of Health in Rome, returning to England in 1961 for the chair of biochemistry at Imperial College, London. During this time he discovered penicillinase – an enzyme that some bacteria can synthesize and so destroy the drug. He also worked on tumor metabolism and the mode of action of insulin in diabetes.