He was born in Redondo Beach, California. He received his Bachelor of Science degree in 1928 and his Master of Science degree in 1929, both from the California Institute of Technology; he then took his Doctor of Philosophy from Princeton University in 1932.
In 1940 he created neptunium ising the cyclotron at Berkeley. In World War II, he was involved in research on radar, sonar, and nuclear weapons. In 1945 he developed ideas for the improvement of the cyclotron, leading to the development of the synchrotron.
In 1946, he became a full professor at Berkeley, and in 1954 he was appointed associate director of the Lawrence Radiation Laboratory, being promoted to director in 1958, where he stayed until his retirement in 1973.