Born in 1926, the son of a furrier.

A Graduate of Harvard University he was a star physicist. Served in the United States Army during World War II. Had leftist beliefs early on, feeling that the Soviet philosophy was more idealogically align with his views. Met Saville “Savy” Sax while attending Harvard, the two sharing common socio-political beliefs.

Was assigned to work on the Manhattan Project in Los Alamos, New Mexico, helping to developed the atomic bomb. Believed that the United States unilateral control over Atomic bomb weaponry gave the country too much power that could lead to possible disaster if there was no other country with the proper tools to serve as a counter-balance. Decided to help to even the balance of power by providing information to the Soviet Union in order to aid them in their own Atomic research. Along with Sax, decided to make contact with Soviet officials to initiate an information transfer.

Sax made contact with Nicola Napoli, the president of Soviet cultural propaganda organization in New York City called Artkino. Sax told Napoli that he had a friend who was privy to top secret atomic research information and wanted to share it with the Soviet Union. Hall at the same time visited the Amtorg, an import/export company that served as a cover for the base of operations for a network of Soviet spies. There he spoke with a warehouse worker who directed him to meet with Sergei Kurnakov, a Soviet journalist based in New York. Napoli had also suggested that Sax meet with Kurnakov.
Hall was scheduled to return to Los Alamos a few days later so Kurnakov was pressed to make a determination whether Sax and Hall were legitimate in their offer or were undercover agents for the FBI. The decision was made that two potential for gaining valuable information far exceeded the accompanying risks.

Moscow received a cable on November 12, 1944, detailing the offer by the young spies. Hall was given the code name “Mlas” which meant young and Sax, a year older than Hall was referred to as “Star” meaning old. Hall obtained and Sax delivered numerous documents and design pals for atomic weapons research including information about implosion experiments to the Soviets.

The United States learned of Hall’s espionage activity when it deciphered intercept Soviet cable messages. These messages, known as the Venona documents provided clear evidence of Hall and Sax. However, the United States, unwilling to alert the Soviets to the fact that they had broken the Soviets code, confronted Hall but did not pursue legal action against him. Hall went on to become a noted biophysicist at Cambridge University, working with biological X-ray research.

In 1996, the Venona documents were made public by the NSA. Hall, in ill health with cancer and Parkinson’s disease, acknowledged that he may have been wrong about the Soviet government, but refused to apologize for his actions. Hall died in 1999.