Josef Frolík was born in Libušín, Czechoslovakia. He graduated from secondary school at the end of World War II. After the war he studied at the business academy in Slaný and worked as an accountant for the state-owned communist newspaper Rudé právo.
Whilst serving his mandatory two years service in the Czechoslovak Peoples' Army Frolík discovered that some officers of the 2nd Infantry Regiment had stolen a small fortune in jewels and paintings. He reported this to the Third Directorate of Counter Intelligence in Prague and was then recruited into the State Security as a 1st Sergeant in the Finance Directorate. He moved on to counter intelligence and from 1964-1966 worked as a spy in London under the guise of a diplomat in the Czechoslovak embassy. He was recalled back to Czechoslovakia and in 1969 he managed to gather as much state secrets as he could and escaped to the west, defecting to the CIA.
After defecting to the West he wrote a book in which he recalled his life and work for the StB and detailed his defection. The Czechoslovak government sentenced him to death in absentia. In 1987 he was diagnosed with cancer and died in May 1989, although some claim that he is still alive in the US using a false identity.
-  - Joseph Frolik - Man in the Wrong Place (Czech)
- Frolik, Joseph (1975). The Frolik Defection - The Memoirs of an Intelligence Agent. Corgi Books. ISBN 0-552-10056-0.