Hall joined the Central Intelligence Agency in 1947, one of the first women hired by the new agency. As a woman she was discriminated against, as the CIA later acknowledged. She was passed over for promotions, honors and work for which she was qualified despite the support and efforts from her superiors who knew her work directly. She was given a desk-bound job as an intelligence analyst to gather information about Soviet penetration of European countries. She resigned in 1948 and then was rehired in 1950 for another desk job.
