Chain is renowned for his role in the discovery of penicillin, a drug that has saved millions of lives and was the first of the antibiotic "wonder drugs." The son of a wealthy chemist, Chain was born in Berlin in 1906. He earned his Ph.D. in chemistry in 1930 from the Friedrich-Wilhelm University in Berlin. When Adolf Hitler (1889-1945) came to power in early 1933, Chain immigrated to England, where he worked and studied under Frederick Gowland Hopkins at Cambridge University.

At the recommendation of Hopkins, Howard Florey invited Chain to join his pathology laboratory at Oxford to pursue studies of antimicrobial agents. While Chain conducted a literature search on lysozyme, an antibacterial enzyme, he came across a paper by Alexander Fleming published in 1929 describing his work with penicillin found in molds. Chain and Florey decided to continue the work, which Fleming had abandoned shortly after his discovery.

Chain conducted the first chemical assay of penicillin. Florey and Chain concluded that penicillin was nontoxic yet effective in destroying a wide range of bacteria, and began conducting clinical trials in humans. The results were so successful that penicillin was quickly put into mass production to treat the infections of wounded soldiers during World War II. In 1945 Chain, Florey, and Fleming were awarded the Nobel Prize in Medicine for discovering penicillin.

Chain went on to discover penicillinase, an enzyme that causes the destruction of penicillin in the body. After World War II, Chain became scientific director of a health institute in Rome, but returned to England in 1961, where he headed a new laboratory at the University of London.