McMillan was born in Redondo Beach, California, on September 18, 1907. He earned his bachelor's degree (1928) and master's degree (1929) at the California Institute of Technology and his doctorate in physics at Princeton in 1932. After a two-year stint with Ernest Orlando Lawrence at the University of California Radiation Laboratory in Berkeley, he joined the faculty at Berkeley in 1935. He became full professor of physics in 1946, associate director of the Radiation Laboratory in 1954, and director in 1958. He remained at the post until his retirement in 1973.

During World War II, McMillan played an important role in the development of microwave radar, sonar, and the atomic bomb. McMillan is best known for two accomplishments, one in the field of chemistry and one in the field of physics. In 1940, while working with Philip Abelson, McMillan discovered the first transuranium element, neptunium. For this discovery, he shared the 1951 Nobel Prize for chemistry with Glenn Seaborg. McMillan's...