After the Second World War Weinberg was accused by the House Un-American Activities Committee of spying on behalf of the Soviet Union, and was later charged with perjury.

[1] Weinberg studied at the University of Wisconsin–Madison from 1938 to 1939 where he met his future wife Merle Hoesly and graduated with a master's degree.

[3] During World War II Weinberg worked at Berkeley's Radiation Laboratory as part of the secret Manhattan Project, developing the atomic bomb.

[4] In 1948 he was appointed an associate professor of physics at the University of Minnesota, where his work included research with Gerald Tauber on the gravitational stability of white dwarfs.

[1] In 1949 the House Un-American Activities Committee opened an investigation into Weinberg, accusing him of being "Scientist X", alleging that he had been sharing atomic secrets with the Soviet Union via communist activist Steve Nelson.